nkeynes@219 | 1 | /**
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nkeynes@223 | 2 | * $Id: rendbkg.c,v 1.3 2006-09-12 12:16:36 nkeynes Exp $
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nkeynes@219 | 3 | *
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nkeynes@219 | 4 | * PVR2 background renderer.
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nkeynes@219 | 5 | *
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nkeynes@219 | 6 | * Yes, it uses the same basic data structure. Yes, it needs to be handled
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nkeynes@219 | 7 | * completely differently.
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nkeynes@219 | 8 | *
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nkeynes@221 | 9 | * Note: this would be really simple if GL did unclamped colour interpolation
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nkeynes@221 | 10 | * but it doesn't (portably), which makes this roughly 2 orders of magnitude
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nkeynes@221 | 11 | * more complicated than it otherwise would be.
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nkeynes@221 | 12 | *
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nkeynes@219 | 13 | * Copyright (c) 2005 Nathan Keynes.
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nkeynes@219 | 14 | *
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nkeynes@219 | 15 | * This program is free software; you can redistribute it and/or modify
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nkeynes@219 | 16 | * it under the terms of the GNU General Public License as published by
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nkeynes@219 | 17 | * the Free Software Foundation; either version 2 of the License, or
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nkeynes@219 | 18 | * (at your option) any later version.
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nkeynes@219 | 19 | *
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nkeynes@219 | 20 | * This program is distributed in the hope that it will be useful,
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nkeynes@219 | 21 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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nkeynes@219 | 22 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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nkeynes@219 | 23 | * GNU General Public License for more details.
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nkeynes@219 | 24 | */
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nkeynes@219 | 25 |
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nkeynes@219 | 26 | #include <sys/time.h>
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nkeynes@219 | 27 | #include "pvr2/pvr2.h"
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nkeynes@221 | 28 | #include <GL/glext.h>
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nkeynes@221 | 29 | #include <math.h>
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nkeynes@219 | 30 |
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nkeynes@221 | 31 | #define MAX_CLAMP_LINES 8
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nkeynes@221 | 32 | #define MAX_VERTEXES 256
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nkeynes@221 | 33 | #define MAX_REGIONS 256
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nkeynes@219 | 34 |
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nkeynes@221 | 35 | /**
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nkeynes@221 | 36 | * Structure to hold an unpacked vertex
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nkeynes@221 | 37 | */
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nkeynes@219 | 38 | struct vertex_all {
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nkeynes@219 | 39 | float x,y,z;
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nkeynes@219 | 40 | float u,v;
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nkeynes@219 | 41 | float rgba[4]; /* Note - RGBA order, as preferred by GL */
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nkeynes@219 | 42 | float spec_rgba[4];
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nkeynes@219 | 43 | };
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nkeynes@219 | 44 |
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nkeynes@219 | 45 | #define FARGB_A(x) (((float)(((x)>>24)+1))/256.0)
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nkeynes@219 | 46 | #define FARGB_R(x) (((float)((((x)>>16)&0xFF)+1))/256.0)
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nkeynes@219 | 47 | #define FARGB_G(x) (((float)((((x)>>8)&0xFF)+1))/256.0)
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nkeynes@219 | 48 | #define FARGB_B(x) (((float)(((x)&0xFF)+1))/256.0)
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nkeynes@219 | 49 |
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nkeynes@219 | 50 | /**
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nkeynes@221 | 51 | * Compute the line where k = target_k, (where k is normally one of
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nkeynes@221 | 52 | * r,g,b,a, or z) and determines the points at which the line intersects
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nkeynes@221 | 53 | * the viewport (0,0,width,height).
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nkeynes@221 | 54 | *
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nkeynes@221 | 55 | * @param center_x the x value for the center position
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nkeynes@221 | 56 | * @param center_y the y value for the center position
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nkeynes@221 | 57 | * @param center_k the k value for the center position
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nkeynes@221 | 58 | * @param width Width of the viewport (ie 640)
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nkeynes@221 | 59 | * @param height Height of the viewport (ie 480)
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nkeynes@221 | 60 | * @param target_k determine the line where k = this value, ie 1.0
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nkeynes@221 | 61 | * @param detxy
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nkeynes@221 | 62 | * @param target Array to write the resultant x,y pairs to (note this
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nkeynes@221 | 63 | * function only sets x and y values).
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nkeynes@221 | 64 | * @return number of vertexes written to the target.
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nkeynes@221 | 65 | */
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nkeynes@221 | 66 | static int compute_colour_line( float center_x, float center_y, float center_k,
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nkeynes@221 | 67 | int width, int height, float target_k,
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nkeynes@221 | 68 | float detxy, float detxk, float detyk,
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nkeynes@221 | 69 | struct vertex_all *target ) {
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nkeynes@221 | 70 | int num_points = 0;
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nkeynes@221 | 71 | float tmpk = (target_k - center_k) * detxy;
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nkeynes@221 | 72 | float x0 = -1;
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nkeynes@221 | 73 | float x1 = -1;
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nkeynes@221 | 74 |
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nkeynes@221 | 75 | if( detyk != 0 ) {
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nkeynes@221 | 76 | x0 = (tmpk - ((0-center_y)*detxk))/detyk + center_x; /* x where y=0 */
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nkeynes@221 | 77 | if( x0 >= 0.0 && x0 <= width ) {
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nkeynes@221 | 78 | target[num_points].x = x0;
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nkeynes@221 | 79 | target[num_points].y = 0.0;
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nkeynes@221 | 80 | num_points++;
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nkeynes@221 | 81 | }
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nkeynes@221 | 82 |
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nkeynes@221 | 83 | x1 = (tmpk - ((height-center_y)*detxk))/detyk + center_x; /* x where y=height */
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nkeynes@221 | 84 | if( x1 >= 0.0 && x1 <= width ) {
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nkeynes@221 | 85 | target[num_points].x = x1;
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nkeynes@221 | 86 | target[num_points].y = height;
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nkeynes@221 | 87 | num_points++;
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nkeynes@221 | 88 | }
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nkeynes@221 | 89 | }
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nkeynes@221 | 90 |
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nkeynes@221 | 91 | if( detxk != 0 ) {
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nkeynes@221 | 92 | if( x0 != 0.0 && x1 != 0.0 ) { /* If x0 == 0 or x1 == 0, then we already have this one */
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nkeynes@221 | 93 | float y0 = (tmpk - ((0-center_x)*detyk))/detxk + center_y; /* y where x=0 */
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nkeynes@221 | 94 | if( y0 >= 0.0 && y0 <= height ) {
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nkeynes@221 | 95 | target[num_points].x = 0.0;
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nkeynes@221 | 96 | target[num_points].y = y0;
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nkeynes@221 | 97 | num_points++;
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nkeynes@221 | 98 | }
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nkeynes@221 | 99 | }
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nkeynes@221 | 100 |
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nkeynes@221 | 101 | if( x0 != width && x1 != width ) {
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nkeynes@221 | 102 | float y1 = (tmpk - ((width-center_x)*detyk))/detxk + center_y; /* y where x=width */
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nkeynes@221 | 103 | if( y1 >= 0.0 && y1 <= height ) {
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nkeynes@221 | 104 | target[num_points].x = width;
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nkeynes@221 | 105 | target[num_points].y = y1;
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nkeynes@221 | 106 | num_points++;
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nkeynes@221 | 107 | }
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nkeynes@221 | 108 | }
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nkeynes@221 | 109 | }
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nkeynes@221 | 110 |
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nkeynes@221 | 111 | if( num_points == 0 || num_points == 2 ) {
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nkeynes@221 | 112 | /* 0 = no points - line doesn't pass through the viewport */
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nkeynes@221 | 113 | /* 2 = normal case - got 2 endpoints */
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nkeynes@221 | 114 | return num_points;
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nkeynes@221 | 115 | } else {
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nkeynes@221 | 116 | ERROR( "compute_colour_line got bad number of points: %d", num_points );
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nkeynes@221 | 117 | return 0;
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nkeynes@221 | 118 | }
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nkeynes@221 | 119 | }
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nkeynes@221 | 120 |
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nkeynes@221 | 121 | /**
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nkeynes@221 | 122 | * A region describes a portion of the screen, possibly subdivided by a line.
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nkeynes@221 | 123 | * if region_left and region_right are -1, this is a terminal region that can
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nkeynes@221 | 124 | * be rendered directly. Otherwise region_left and region_right refer two
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nkeynes@221 | 125 | * sub-regions that are separated by the line segment vertex1-vertex2.
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nkeynes@221 | 126 | */
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nkeynes@221 | 127 | struct bkg_region {
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nkeynes@221 | 128 | /* Vertexes marking the line segment that splits this region */
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nkeynes@221 | 129 | int vertex1;
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nkeynes@221 | 130 | int vertex2;
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nkeynes@221 | 131 | /* Index of the left sub-region */
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nkeynes@221 | 132 | int region_left;
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nkeynes@221 | 133 | /* Index of the right sub-region */
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nkeynes@221 | 134 | int region_right;
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nkeynes@221 | 135 | };
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nkeynes@221 | 136 |
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nkeynes@221 | 137 | /**
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nkeynes@221 | 138 | * Convenience structure to bundle together the vertex and region data.
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nkeynes@221 | 139 | */
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nkeynes@221 | 140 | struct bkg_scene {
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nkeynes@221 | 141 | int num_vertexes;
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nkeynes@221 | 142 | int num_regions;
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nkeynes@221 | 143 | struct vertex_all vertexes[MAX_VERTEXES];
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nkeynes@221 | 144 | struct bkg_region regions[MAX_REGIONS];
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nkeynes@221 | 145 | };
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nkeynes@221 | 146 |
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nkeynes@221 | 147 | void parse_vertexes( uint32_t *polygon, int num_vertexes, struct vertex_all *result )
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nkeynes@221 | 148 | {
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nkeynes@221 | 149 | uint32_t *vertexes = polygon + 3;
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nkeynes@221 | 150 | int i,m = 0;
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nkeynes@221 | 151 | for( i=0; i<num_vertexes; i++ ) {
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nkeynes@221 | 152 | float *vertexf = (float *)vertexes;
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nkeynes@221 | 153 | result[i].x = vertexf[0];
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nkeynes@221 | 154 | result[i].y = vertexf[1];
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nkeynes@221 | 155 | result[i].z = vertexf[2];
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nkeynes@221 | 156 | uint32_t argb;
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nkeynes@221 | 157 | if( POLY1_TEXTURED(*polygon) ) {
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nkeynes@221 | 158 | if( POLY1_UV16(*polygon) ) {
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nkeynes@221 | 159 | result[i].u = halftofloat(vertexes[m+3]>>16);
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nkeynes@221 | 160 | result[i].v = halftofloat(vertexes[m+3]);
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nkeynes@221 | 161 | argb = vertexes[m+4];
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nkeynes@221 | 162 | vertexes += 5;
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nkeynes@221 | 163 | } else {
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nkeynes@221 | 164 | result[i].u = vertexf[m+3];
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nkeynes@221 | 165 | result[i].v = vertexf[m+4];
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nkeynes@221 | 166 | argb = vertexes[m+5];
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nkeynes@221 | 167 | vertexes += 6;
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nkeynes@221 | 168 | }
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nkeynes@221 | 169 | } else {
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nkeynes@221 | 170 | argb = vertexes[m+3];
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nkeynes@221 | 171 | vertexes += 4;
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nkeynes@221 | 172 | }
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nkeynes@221 | 173 | result[i].rgba[0] = FARGB_R(argb);
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nkeynes@221 | 174 | result[i].rgba[1] = FARGB_G(argb);
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nkeynes@221 | 175 | result[i].rgba[2] = FARGB_B(argb);
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nkeynes@221 | 176 | result[i].rgba[3] = FARGB_A(argb);
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nkeynes@221 | 177 | }
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nkeynes@221 | 178 |
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nkeynes@221 | 179 | }
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nkeynes@221 | 180 |
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nkeynes@221 | 181 | /**
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nkeynes@221 | 182 | * Constants returned by compute_line_intersection. Note that for these purposes,
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nkeynes@221 | 183 | * "Left" means the point(s) result in a negative value in the line equation, while
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nkeynes@221 | 184 | * "Right" means the points(s) result in a positive value in the line equation. The
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nkeynes@221 | 185 | * exact meaning isn't particularly important though, as long as we're consistent
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nkeynes@221 | 186 | * throughout this process
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nkeynes@221 | 187 | */
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nkeynes@221 | 188 | #define LINE_COLLINEAR 0 /* The line segments are part of the same line */
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nkeynes@221 | 189 | #define LINE_SIDE_LEFT 1 /* The second line is entirely to the "left" of the first line */
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nkeynes@221 | 190 | #define LINE_SIDE_RIGHT 2 /* The second line is entirely to the "right" of the first line */
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nkeynes@221 | 191 | #define LINE_INTERSECT_FROM_LEFT 3 /* The lines intersect, and (x3,y3) is to the "left" of the first line */
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nkeynes@221 | 192 | #define LINE_INTERSECT_FROM_RIGHT 4 /* The lines intersect, and (x3,y3) is to the "right" of the first line */
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nkeynes@221 | 193 | #define LINE_SKEW 5 /* The line segments neither intersect nor do any of the above apply (should never happen here) */
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nkeynes@221 | 194 |
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nkeynes@221 | 195 | /**
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nkeynes@221 | 196 | * Compute the intersection of two line segments, where
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nkeynes@221 | 197 | * (x1,y1)-(x2,y2) defines the target segment, and
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nkeynes@221 | 198 | * (x3,y3)-(x4,y4) defines the line intersecting it.
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nkeynes@221 | 199 | *
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nkeynes@221 | 200 | * Based off work by Mukesh Prasad (http://www.acm.org/pubs/tog/GraphicsGems/index.html)
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nkeynes@221 | 201 | *
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nkeynes@221 | 202 | * @return one of the above LINE_* constants
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nkeynes@221 | 203 | */
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nkeynes@221 | 204 | static int compute_line_intersection( float x1, float y1, /* First line segment */
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nkeynes@221 | 205 | float x2, float y2,
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nkeynes@221 | 206 | float x3, float y3, /* Second line segment */
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nkeynes@221 | 207 | float x4, float y4,
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nkeynes@221 | 208 | float *x, float *y ) /* Output value: */
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nkeynes@221 | 209 | {
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nkeynes@221 | 210 | float a1, a2, b1, b2, c1, c2; /* Coefficients of line eqns. */
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nkeynes@221 | 211 | float r1, r2, r3, r4; /* test values */
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nkeynes@221 | 212 | float denom; /* Intermediate values */
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nkeynes@221 | 213 |
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nkeynes@221 | 214 | /* Compute a1, b1, c1, where line joining points 1 and 2
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nkeynes@221 | 215 | * is "a1 x + b1 y + c1 = 0".
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nkeynes@221 | 216 | */
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nkeynes@221 | 217 |
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nkeynes@221 | 218 | a1 = y2 - y1;
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nkeynes@221 | 219 | b1 = x1 - x2;
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nkeynes@221 | 220 | c1 = x2 * y1 - x1 * y2;
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nkeynes@221 | 221 |
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nkeynes@221 | 222 | /* Compute r3 and r4. */
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nkeynes@221 | 223 |
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nkeynes@221 | 224 | r3 = a1 * x3 + b1 * y3 + c1;
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nkeynes@221 | 225 | r4 = a1 * x4 + b1 * y4 + c1;
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nkeynes@221 | 226 |
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nkeynes@221 | 227 | /* Check signs of r3 and r4. If both point 3 and point 4 lie on
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nkeynes@221 | 228 | * same side of line 1, the line segments do not intersect.
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nkeynes@221 | 229 | */
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nkeynes@221 | 230 |
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nkeynes@221 | 231 | if( r3 == 0 && r4 == 0 ) {
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nkeynes@221 | 232 | return LINE_COLLINEAR;
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nkeynes@221 | 233 | } else if( r3 <= 0 && r4 <= 0 ) {
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nkeynes@221 | 234 | return LINE_SIDE_LEFT;
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nkeynes@221 | 235 | } else if( r3 >= 0 && r4 >= 0 ) {
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nkeynes@221 | 236 | return LINE_SIDE_RIGHT;
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nkeynes@221 | 237 | }
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nkeynes@221 | 238 |
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nkeynes@221 | 239 | /* Compute a2, b2, c2 */
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nkeynes@221 | 240 |
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nkeynes@221 | 241 | a2 = y4 - y3;
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nkeynes@221 | 242 | b2 = x3 - x4;
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nkeynes@221 | 243 | c2 = x4 * y3 - x3 * y4;
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nkeynes@221 | 244 |
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nkeynes@221 | 245 | /* Compute r1 and r2 */
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nkeynes@221 | 246 |
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nkeynes@221 | 247 | r1 = a2 * x1 + b2 * y1 + c2;
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nkeynes@221 | 248 | r2 = a2 * x2 + b2 * y2 + c2;
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nkeynes@221 | 249 |
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nkeynes@221 | 250 | /* Check signs of r1 and r2. If both point 1 and point 2 lie
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nkeynes@221 | 251 | * on same side of second line segment, the line segments do
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nkeynes@221 | 252 | * not intersect.
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nkeynes@221 | 253 | */
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nkeynes@221 | 254 |
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nkeynes@221 | 255 | if ( r1 != 0 && r2 != 0 &&
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nkeynes@221 | 256 | signbit(r1) == signbit(r2) ) {
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nkeynes@221 | 257 | return LINE_SKEW; /* Should never happen */
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nkeynes@221 | 258 | }
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nkeynes@221 | 259 |
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nkeynes@221 | 260 | /* Cmpute intersection point.
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nkeynes@221 | 261 | */
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nkeynes@221 | 262 | denom = a1 * b2 - a2 * b1;
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nkeynes@221 | 263 | if ( denom == 0 )
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nkeynes@221 | 264 | return LINE_COLLINEAR; /* Should never get to this point either */
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nkeynes@221 | 265 |
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nkeynes@221 | 266 | *x = (b1 * c2 - b2 * c1) / denom;
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nkeynes@221 | 267 | *y = (a2 * c1 - a1 * c2) / denom;
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nkeynes@221 | 268 |
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nkeynes@221 | 269 | if( r3 <= 0 && r4 >= 0 ) {
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nkeynes@221 | 270 | return LINE_INTERSECT_FROM_LEFT;
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nkeynes@221 | 271 | } else {
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nkeynes@221 | 272 | return LINE_INTERSECT_FROM_RIGHT;
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nkeynes@221 | 273 | }
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nkeynes@221 | 274 | }
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nkeynes@221 | 275 |
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nkeynes@221 | 276 | /**
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nkeynes@221 | 277 | * Given a set of vertexes and a line segment to use to split them, generates
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nkeynes@221 | 278 | * two sets of vertexes representing the polygon on either side of the line
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nkeynes@221 | 279 | * segment. This method preserves the winding direction of the input vertexes.
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nkeynes@221 | 280 | */
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nkeynes@221 | 281 | static void compute_subregions( struct bkg_scene *scene,
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nkeynes@221 | 282 | int splitv1, int splitv2,
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nkeynes@221 | 283 | int *vertex_in, int num_vertex_in,
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nkeynes@221 | 284 | int *left_vertex_out, int *num_left_vertex_out,
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nkeynes@221 | 285 | int *right_vertex_out, int *num_right_vertex_out )
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nkeynes@221 | 286 | {
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nkeynes@221 | 287 | float x1 = scene->vertexes[splitv1].x;
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nkeynes@221 | 288 | float y1 = scene->vertexes[splitv1].y;
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nkeynes@221 | 289 | float x2 = scene->vertexes[splitv2].x;
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nkeynes@221 | 290 | float y2 = scene->vertexes[splitv2].y;
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nkeynes@221 | 291 |
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nkeynes@221 | 292 | float a1 = y2 - y1;
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nkeynes@221 | 293 | float b1 = x1 - x2;
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nkeynes@221 | 294 | float c1 = x2 * y1 - x1 * y2;
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nkeynes@221 | 295 | int i;
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nkeynes@221 | 296 |
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nkeynes@221 | 297 | *num_left_vertex_out = 0;
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nkeynes@221 | 298 | *num_right_vertex_out = 0;
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nkeynes@221 | 299 | int last = 0;
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nkeynes@221 | 300 | for( i=0; i<num_vertex_in; i++ ) {
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nkeynes@221 | 301 | struct vertex_all *vertex = &scene->vertexes[vertex_in[i]];
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nkeynes@221 | 302 | float r = a1 * vertex->x + b1 * vertex->y + c1;
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nkeynes@221 | 303 | if( r <= 0 ) {
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nkeynes@221 | 304 | if( last == 1 ) {
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nkeynes@221 | 305 | /* cross-point. add the split vertexes */
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nkeynes@221 | 306 | int v1 = vertex_in[i-1];
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nkeynes@221 | 307 | int v2 = vertex_in[i];
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nkeynes@221 | 308 | /* Determine which point is closer to the line. Strictly speaking
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nkeynes@221 | 309 | * one of them must be ON the line, but this way allows for floating
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nkeynes@221 | 310 | * point inaccuracies.
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nkeynes@221 | 311 | */
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nkeynes@221 | 312 | float a2 = scene->vertexes[v2].y - scene->vertexes[v1].y;
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nkeynes@221 | 313 | float b2 = scene->vertexes[v1].x - scene->vertexes[v2].x;
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nkeynes@221 | 314 | float c2 = scene->vertexes[v2].x * scene->vertexes[v1].y -
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nkeynes@221 | 315 | scene->vertexes[v1].x * scene->vertexes[v2].y;
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nkeynes@221 | 316 | float r1 = a2 * x1 + b2 * y1 + c2;
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nkeynes@221 | 317 | float r2 = a2 * x2 + b2 * y2 + c2;
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nkeynes@221 | 318 | if( fabsf(r1) > fabs(r2) ) {
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nkeynes@221 | 319 | int tmp = splitv1;
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nkeynes@221 | 320 | splitv1 = splitv2;
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nkeynes@221 | 321 | splitv2 = tmp;
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nkeynes@221 | 322 | }
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nkeynes@221 | 323 | right_vertex_out[(*num_right_vertex_out)++] = splitv1;
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nkeynes@221 | 324 | right_vertex_out[(*num_right_vertex_out)++] = splitv2;
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nkeynes@221 | 325 | left_vertex_out[(*num_left_vertex_out)++] = splitv2;
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nkeynes@221 | 326 | left_vertex_out[(*num_left_vertex_out)++] = splitv1;
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nkeynes@221 | 327 | last = 2;
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nkeynes@221 | 328 | } else if( last != 2 ) {
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nkeynes@221 | 329 | last = -1;
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nkeynes@221 | 330 | }
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nkeynes@221 | 331 | left_vertex_out[(*num_left_vertex_out)++] = vertex_in[i];
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nkeynes@221 | 332 | } else {
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nkeynes@221 | 333 | if( last == -1 ) {
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nkeynes@221 | 334 | /* cross-point. add the split vertexes */
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nkeynes@221 | 335 | int v1 = vertex_in[i-1];
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nkeynes@221 | 336 | int v2 = vertex_in[i];
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nkeynes@221 | 337 | /* Determine which point is closer to the line. Strictly speaking
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nkeynes@221 | 338 | * one of them must be ON the line, but this way allows for floating
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nkeynes@221 | 339 | * point inaccuracies.
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nkeynes@221 | 340 | */
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nkeynes@221 | 341 | float a2 = scene->vertexes[v2].y - scene->vertexes[v1].y;
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nkeynes@221 | 342 | float b2 = scene->vertexes[v1].x - scene->vertexes[v2].x;
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nkeynes@221 | 343 | float c2 = scene->vertexes[v2].x * scene->vertexes[v1].y -
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nkeynes@221 | 344 | scene->vertexes[v1].x * scene->vertexes[v2].y;
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nkeynes@221 | 345 | float r1 = a2 * x1 + b2 * y1 + c2;
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nkeynes@221 | 346 | float r2 = a2 * x2 + b2 * y2 + c2;
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nkeynes@221 | 347 | if( fabsf(r1) > fabs(r2) ) {
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nkeynes@221 | 348 | int tmp = splitv1;
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nkeynes@221 | 349 | splitv1 = splitv2;
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nkeynes@221 | 350 | splitv2 = tmp;
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nkeynes@221 | 351 | }
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nkeynes@221 | 352 | left_vertex_out[(*num_left_vertex_out)++] = splitv1;
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nkeynes@221 | 353 | left_vertex_out[(*num_left_vertex_out)++] = splitv2;
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nkeynes@221 | 354 | right_vertex_out[(*num_right_vertex_out)++] = splitv2;
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nkeynes@221 | 355 | right_vertex_out[(*num_right_vertex_out)++] = splitv1;
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nkeynes@221 | 356 | last = 2;
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nkeynes@221 | 357 | } else if( last != 2 ) {
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nkeynes@221 | 358 | last = 1;
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nkeynes@221 | 359 | }
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nkeynes@221 | 360 | right_vertex_out[(*num_right_vertex_out)++] = vertex_in[i];
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nkeynes@221 | 361 | }
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nkeynes@221 | 362 | }
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nkeynes@221 | 363 | }
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nkeynes@221 | 364 |
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nkeynes@221 | 365 | /**
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nkeynes@221 | 366 | * Subdivide the region tree by splitting it along a given line.
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nkeynes@221 | 367 | *
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nkeynes@221 | 368 | * @param scene current bkg scene data
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nkeynes@221 | 369 | * @param region current region under examination
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nkeynes@221 | 370 | * @param vertex1 first vertex of the new line segment
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nkeynes@221 | 371 | * @param vertex2 second vertex of the new line segment
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nkeynes@221 | 372 | */
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nkeynes@221 | 373 | static void bkg_region_subdivide( struct bkg_scene *scene, int region, int vertex1, int vertex2 ) {
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nkeynes@221 | 374 | struct bkg_region *this_region = &scene->regions[region];
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nkeynes@221 | 375 |
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nkeynes@221 | 376 | if( scene->regions[region].region_left == -1 || scene->regions[region].region_right == -1 ) {
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nkeynes@221 | 377 | /* Reached the end of the tree. Setup new left+right regions */
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nkeynes@221 | 378 | int i = scene->num_regions;
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nkeynes@221 | 379 | scene->regions[i].region_left = scene->regions[i].region_right = -1;
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nkeynes@221 | 380 | scene->regions[i+1].region_left = scene->regions[i+1].region_right = -1;
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nkeynes@221 | 381 | this_region->region_left = i;
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nkeynes@221 | 382 | this_region->region_right = i+1;
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nkeynes@221 | 383 | this_region->vertex1 = vertex1;
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nkeynes@221 | 384 | this_region->vertex2 = vertex2;
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nkeynes@221 | 385 | scene->num_regions += 2;
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nkeynes@221 | 386 | } else {
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nkeynes@221 | 387 | float x,y;
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nkeynes@221 | 388 | int thisv1 = this_region->vertex1;
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nkeynes@221 | 389 | int thisv2 = this_region->vertex2;
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nkeynes@221 | 390 | int vertex3;
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nkeynes@221 | 391 | int status =
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nkeynes@221 | 392 | compute_line_intersection( scene->vertexes[thisv1].x, scene->vertexes[thisv1].y,
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nkeynes@221 | 393 | scene->vertexes[thisv2].x, scene->vertexes[thisv2].y,
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nkeynes@221 | 394 | scene->vertexes[vertex1].x, scene->vertexes[vertex1].y,
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nkeynes@221 | 395 | scene->vertexes[vertex2].x, scene->vertexes[vertex2].y,
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nkeynes@221 | 396 | &x, &y );
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nkeynes@221 | 397 | switch( status ) {
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nkeynes@221 | 398 | case LINE_INTERSECT_FROM_LEFT:
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nkeynes@221 | 399 | /* if new line segment intersects our current line segment,
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nkeynes@221 | 400 | * subdivide the segment (add a new vertex) and recurse on both
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nkeynes@221 | 401 | * sub trees
|
nkeynes@221 | 402 | */
|
nkeynes@221 | 403 | /* Compute split-point vertex */
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nkeynes@221 | 404 | vertex3 = scene->num_vertexes++;
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nkeynes@221 | 405 | scene->vertexes[vertex3].x = x;
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nkeynes@221 | 406 | scene->vertexes[vertex3].y = y;
|
nkeynes@221 | 407 | /* Recurse */
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nkeynes@221 | 408 | bkg_region_subdivide( scene, scene->regions[region].region_left, vertex1,vertex3 );
|
nkeynes@221 | 409 | bkg_region_subdivide( scene, scene->regions[region].region_right, vertex3, vertex2 );
|
nkeynes@221 | 410 | break;
|
nkeynes@221 | 411 | case LINE_INTERSECT_FROM_RIGHT:
|
nkeynes@221 | 412 | /* Same except line runs in the opposite direction */
|
nkeynes@221 | 413 | vertex3 = scene->num_vertexes++;
|
nkeynes@221 | 414 | scene->vertexes[vertex3].x = x;
|
nkeynes@221 | 415 | scene->vertexes[vertex3].y = y;
|
nkeynes@221 | 416 | /* Recurse */
|
nkeynes@221 | 417 | bkg_region_subdivide( scene, scene->regions[region].region_left, vertex2,vertex3 );
|
nkeynes@221 | 418 | bkg_region_subdivide( scene, scene->regions[region].region_right, vertex3, vertex1 );
|
nkeynes@221 | 419 | break;
|
nkeynes@221 | 420 | case LINE_COLLINEAR:
|
nkeynes@221 | 421 | case LINE_SKEW:
|
nkeynes@221 | 422 | /* Collinear - ignore */
|
nkeynes@221 | 423 | break;
|
nkeynes@221 | 424 | case LINE_SIDE_LEFT:
|
nkeynes@221 | 425 | /* else if line segment passes through the left sub-region alone,
|
nkeynes@221 | 426 | * left-recurse only.
|
nkeynes@221 | 427 | */
|
nkeynes@221 | 428 | bkg_region_subdivide( scene, scene->regions[region].region_left, vertex1, vertex2 );
|
nkeynes@221 | 429 | break;
|
nkeynes@221 | 430 | case LINE_SIDE_RIGHT:
|
nkeynes@221 | 431 | /* Otherwise line segment passes through the right sub-region alone,
|
nkeynes@221 | 432 | * so right-recurse.
|
nkeynes@221 | 433 | */
|
nkeynes@221 | 434 | bkg_region_subdivide( scene, scene->regions[region].region_right, vertex1, vertex2 );
|
nkeynes@221 | 435 | break;
|
nkeynes@221 | 436 | }
|
nkeynes@221 | 437 | }
|
nkeynes@221 | 438 | }
|
nkeynes@221 | 439 |
|
nkeynes@221 | 440 |
|
nkeynes@221 | 441 |
|
nkeynes@221 | 442 | /**
|
nkeynes@219 | 443 | * Compute the values for an array of vertexes, given x,y for each
|
nkeynes@219 | 444 | * vertex and the base 3-vertex triple used to define the background
|
nkeynes@219 | 445 | * plane. Essentially the base vertexes are used to find the
|
nkeynes@219 | 446 | * plane equation for each of z,a,r,g,b,etc, which is then solved for
|
nkeynes@219 | 447 | * each of the required compute vertexes (normally the corner points).
|
nkeynes@219 | 448 | *
|
nkeynes@219 | 449 | * @param base The 3 vertexes supplied as the background definition
|
nkeynes@219 | 450 | * @param compute An array of vertexes to compute. x and y must be
|
nkeynes@219 | 451 | * preset, other values are computed.
|
nkeynes@219 | 452 | */
|
nkeynes@221 | 453 | static void bkg_compute_scene( struct vertex_all *base, int width, int height,
|
nkeynes@221 | 454 | struct bkg_scene *scene )
|
nkeynes@219 | 455 | {
|
nkeynes@219 | 456 | struct vertex_all center;
|
nkeynes@219 | 457 | struct vertex_all diff0, diff1;
|
nkeynes@221 | 458 | int i,k;
|
nkeynes@219 | 459 |
|
nkeynes@219 | 460 | center.x = base[1].x;
|
nkeynes@219 | 461 | center.y = base[1].y;
|
nkeynes@219 | 462 | center.z = base[1].z;
|
nkeynes@219 | 463 | diff0.x = base[0].x - base[1].x;
|
nkeynes@219 | 464 | diff0.y = base[0].y - base[1].y;
|
nkeynes@219 | 465 | diff0.z = base[0].z - base[1].z;
|
nkeynes@219 | 466 | diff1.x = base[2].x - base[1].x;
|
nkeynes@219 | 467 | diff1.y = base[2].y - base[1].y;
|
nkeynes@219 | 468 | diff1.z = base[2].z - base[1].z;
|
nkeynes@219 | 469 |
|
nkeynes@221 | 470 | float detxy = ((diff1.y) * (diff0.x)) - ((diff0.y) * (diff1.x));
|
nkeynes@221 | 471 |
|
nkeynes@221 | 472 | /* Corner points first */
|
nkeynes@221 | 473 | scene->vertexes[0].x = 0.0;
|
nkeynes@221 | 474 | scene->vertexes[0].y = 0.0;
|
nkeynes@221 | 475 | scene->vertexes[1].x = width;
|
nkeynes@221 | 476 | scene->vertexes[1].y = 0.0;
|
nkeynes@221 | 477 | scene->vertexes[2].x = width;
|
nkeynes@221 | 478 | scene->vertexes[2].y = height;
|
nkeynes@221 | 479 | scene->vertexes[3].x = 0.0;
|
nkeynes@221 | 480 | scene->vertexes[3].y = height;
|
nkeynes@221 | 481 | scene->regions[0].region_left = -1;
|
nkeynes@221 | 482 | scene->regions[0].region_right = -1;
|
nkeynes@221 | 483 | scene->num_vertexes = 4;
|
nkeynes@221 | 484 | scene->num_regions = 1;
|
nkeynes@221 | 485 |
|
nkeynes@221 | 486 | if( detxy == 0 ) {
|
nkeynes@221 | 487 | /* The points lie on a single line - no plane for you. Use the values
|
nkeynes@221 | 488 | * from the 3rd point for the whole screen.
|
nkeynes@221 | 489 | */
|
nkeynes@221 | 490 | for( i=0; i<4; i++ ) {
|
nkeynes@221 | 491 | scene->vertexes[i].rgba[0] = base[2].rgba[0];
|
nkeynes@221 | 492 | scene->vertexes[i].rgba[1] = base[2].rgba[1];
|
nkeynes@221 | 493 | scene->vertexes[i].rgba[2] = base[2].rgba[2];
|
nkeynes@221 | 494 | scene->vertexes[i].rgba[3] = base[2].rgba[3];
|
nkeynes@221 | 495 | scene->vertexes[i].u = base[2].u;
|
nkeynes@221 | 496 | scene->vertexes[i].v = base[2].v;
|
nkeynes@221 | 497 | }
|
nkeynes@219 | 498 | } else {
|
nkeynes@221 | 499 | /* Compute the colour values at each corner */
|
nkeynes@221 | 500 | center.rgba[0] = base[1].rgba[0];
|
nkeynes@221 | 501 | center.rgba[1] = base[1].rgba[1];
|
nkeynes@221 | 502 | center.rgba[2] = base[1].rgba[2];
|
nkeynes@221 | 503 | center.rgba[3] = base[1].rgba[3];
|
nkeynes@221 | 504 | diff0.rgba[0] = base[0].rgba[0] - center.rgba[0];
|
nkeynes@221 | 505 | diff0.rgba[1] = base[0].rgba[1] - center.rgba[1];
|
nkeynes@221 | 506 | diff0.rgba[2] = base[0].rgba[2] - center.rgba[2];
|
nkeynes@221 | 507 | diff0.rgba[3] = base[0].rgba[3] - center.rgba[3];
|
nkeynes@221 | 508 | diff0.u = base[0].u - center.u;
|
nkeynes@221 | 509 | diff0.v = base[0].v - center.v;
|
nkeynes@221 | 510 | diff1.rgba[0] = base[2].rgba[0] - center.rgba[0];
|
nkeynes@221 | 511 | diff1.rgba[1] = base[2].rgba[1] - center.rgba[1];
|
nkeynes@221 | 512 | diff1.rgba[2] = base[2].rgba[2] - center.rgba[2];
|
nkeynes@221 | 513 | diff1.rgba[3] = base[2].rgba[3] - center.rgba[3];
|
nkeynes@221 | 514 | diff1.u = base[2].u - center.u;
|
nkeynes@221 | 515 | diff1.v = base[2].v - center.v;
|
nkeynes@221 | 516 | for( i=0; i<4; i++ ) {
|
nkeynes@221 | 517 | float t = ((scene->vertexes[i].x - center.x) * diff1.y -
|
nkeynes@221 | 518 | (scene->vertexes[i].y - center.y) * diff1.x) / detxy;
|
nkeynes@221 | 519 | float s = ((scene->vertexes[i].y - center.y) * diff0.x -
|
nkeynes@221 | 520 | (scene->vertexes[i].x - center.x) * diff0.y) / detxy;
|
nkeynes@221 | 521 | scene->vertexes[i].z = center.z + (t*diff0.z) + (s*diff1.z);
|
nkeynes@221 | 522 | scene->vertexes[i].rgba[0] = center.rgba[0] + (t*diff0.rgba[0]) + (s*diff1.rgba[0]);
|
nkeynes@221 | 523 | scene->vertexes[i].rgba[1] = center.rgba[1] + (t*diff0.rgba[1]) + (s*diff1.rgba[1]);
|
nkeynes@221 | 524 | scene->vertexes[i].rgba[2] = center.rgba[2] + (t*diff0.rgba[2]) + (s*diff1.rgba[2]);
|
nkeynes@221 | 525 | scene->vertexes[i].rgba[3] = center.rgba[3] + (t*diff0.rgba[3]) + (s*diff1.rgba[3]);
|
nkeynes@221 | 526 | scene->vertexes[i].u = center.u + (t*diff0.u) + (s*diff1.u);
|
nkeynes@221 | 527 | scene->vertexes[i].v = center.v + (t*diff0.v) + (s*diff1.v);
|
nkeynes@221 | 528 | }
|
nkeynes@221 | 529 |
|
nkeynes@221 | 530 | /* Check for values > 1.0 | < 0.0 */
|
nkeynes@221 | 531 | for( k=0; k<4; k++ ) {
|
nkeynes@221 | 532 | float detyk = ((diff1.y) * (diff0.rgba[k])) - ((diff0.y)*(diff1.rgba[k]));
|
nkeynes@221 | 533 | float detxk = ((diff0.x) * (diff1.rgba[k])) - ((diff1.x)*(diff0.rgba[k]));
|
nkeynes@221 | 534 | if( scene->vertexes[0].rgba[k] > 1.0 || scene->vertexes[1].rgba[k] > 1.0 ||
|
nkeynes@221 | 535 | scene->vertexes[2].rgba[k] > 1.0 || scene->vertexes[3].rgba[k] > 1.0 ) {
|
nkeynes@221 | 536 | int v1 = scene->num_vertexes;
|
nkeynes@221 | 537 | scene->num_vertexes += compute_colour_line(center.x, center.y, center.rgba[k],
|
nkeynes@221 | 538 | width, height, 1.0,
|
nkeynes@221 | 539 | detxy, detxk, detyk,
|
nkeynes@221 | 540 | scene->vertexes+scene->num_vertexes );
|
nkeynes@221 | 541 | if( scene->num_vertexes != v1 ) {
|
nkeynes@221 | 542 | bkg_region_subdivide( scene, 0, v1, v1+1 );
|
nkeynes@221 | 543 | }
|
nkeynes@221 | 544 | }
|
nkeynes@221 | 545 |
|
nkeynes@221 | 546 | if( scene->vertexes[0].rgba[k] < 0.0 || scene->vertexes[1].rgba[k] < 0.0 ||
|
nkeynes@221 | 547 | scene->vertexes[2].rgba[k] < 0.0 || scene->vertexes[3].rgba[k] < 0.0 ) {
|
nkeynes@221 | 548 | int v1 = scene->num_vertexes;
|
nkeynes@221 | 549 | scene->num_vertexes += compute_colour_line(center.x, center.y, center.rgba[k],
|
nkeynes@221 | 550 | width, height, 0.0,
|
nkeynes@221 | 551 | detxy, detxk, detyk,
|
nkeynes@221 | 552 | scene->vertexes+scene->num_vertexes );
|
nkeynes@221 | 553 | if( scene->num_vertexes != v1 ) {
|
nkeynes@221 | 554 | bkg_region_subdivide( scene, 0, v1, v1+1 );
|
nkeynes@221 | 555 | }
|
nkeynes@221 | 556 |
|
nkeynes@221 | 557 | }
|
nkeynes@221 | 558 | }
|
nkeynes@221 | 559 |
|
nkeynes@221 | 560 | /* Finally compute the colour values for all vertexes
|
nkeynes@221 | 561 | * (excluding the 4 we did upfront) */
|
nkeynes@221 | 562 | for( i=4; i<scene->num_vertexes; i++ ) {
|
nkeynes@221 | 563 | float t = ((scene->vertexes[i].x - center.x) * diff1.y -
|
nkeynes@221 | 564 | (scene->vertexes[i].y - center.y) * diff1.x) / detxy;
|
nkeynes@221 | 565 | float s = ((scene->vertexes[i].y - center.y) * diff0.x -
|
nkeynes@221 | 566 | (scene->vertexes[i].x - center.x) * diff0.y) / detxy;
|
nkeynes@221 | 567 | scene->vertexes[i].z = center.z + (t*diff0.z) + (s*diff1.z);
|
nkeynes@221 | 568 | scene->vertexes[i].rgba[0] = center.rgba[0] + (t*diff0.rgba[0]) + (s*diff1.rgba[0]);
|
nkeynes@221 | 569 | scene->vertexes[i].rgba[1] = center.rgba[1] + (t*diff0.rgba[1]) + (s*diff1.rgba[1]);
|
nkeynes@221 | 570 | scene->vertexes[i].rgba[2] = center.rgba[2] + (t*diff0.rgba[2]) + (s*diff1.rgba[2]);
|
nkeynes@221 | 571 | scene->vertexes[i].rgba[3] = center.rgba[3] + (t*diff0.rgba[3]) + (s*diff1.rgba[3]);
|
nkeynes@221 | 572 | scene->vertexes[i].u = center.u + (t*diff0.u) + (s*diff1.u);
|
nkeynes@221 | 573 | scene->vertexes[i].v = center.v + (t*diff0.v) + (s*diff1.v);
|
nkeynes@219 | 574 | }
|
nkeynes@219 | 575 | }
|
nkeynes@219 | 576 | }
|
nkeynes@219 | 577 |
|
nkeynes@221 | 578 | /**
|
nkeynes@221 | 579 | * Render a bkg_region.
|
nkeynes@221 | 580 | * @param scene the background scene data
|
nkeynes@221 | 581 | * @param region the region to render
|
nkeynes@221 | 582 | * @param vertexes the vertexes surrounding the region
|
nkeynes@221 | 583 | * @param num_vertexes the number of vertexes in the vertex array
|
nkeynes@221 | 584 | */
|
nkeynes@221 | 585 | void bkg_render_region( struct bkg_scene *scene, int region, int *vertexes, int num_vertexes,
|
nkeynes@221 | 586 | uint32_t poly1 )
|
nkeynes@221 | 587 | {
|
nkeynes@221 | 588 | if( scene->regions[region].region_left == -1 && scene->regions[region].region_right == -1 ) {
|
nkeynes@221 | 589 | /* Leaf node - render the points as given */
|
nkeynes@221 | 590 | int i,k;
|
nkeynes@221 | 591 | glBegin(GL_POLYGON);
|
nkeynes@221 | 592 | for( i=0; i<num_vertexes; i++ ) {
|
nkeynes@221 | 593 | k = vertexes[i];
|
nkeynes@221 | 594 | glColor4fv(scene->vertexes[k].rgba);
|
nkeynes@221 | 595 | if( POLY1_TEXTURED(poly1) ) {
|
nkeynes@221 | 596 | glTexCoord2f(scene->vertexes[k].u, scene->vertexes[k].v);
|
nkeynes@221 | 597 | }
|
nkeynes@221 | 598 | glVertex3f(scene->vertexes[k].x, scene->vertexes[k].y, scene->vertexes[k].z);
|
nkeynes@221 | 599 | }
|
nkeynes@221 | 600 | glEnd();
|
nkeynes@221 | 601 | } else {
|
nkeynes@221 | 602 | /* split the region into left and right regions */
|
nkeynes@221 | 603 | int left_vertexes[num_vertexes+1];
|
nkeynes@221 | 604 | int right_vertexes[num_vertexes+1];
|
nkeynes@221 | 605 | int num_left = 0;
|
nkeynes@221 | 606 | int num_right = 0;
|
nkeynes@221 | 607 | struct bkg_region *reg = &scene->regions[region];
|
nkeynes@221 | 608 | compute_subregions( scene, reg->vertex1, reg->vertex2, vertexes, num_vertexes,
|
nkeynes@221 | 609 | left_vertexes, &num_left, right_vertexes, &num_right );
|
nkeynes@221 | 610 | bkg_render_region( scene, reg->region_left, left_vertexes, num_left, poly1 );
|
nkeynes@221 | 611 | bkg_render_region( scene, reg->region_right, right_vertexes, num_right, poly1 );
|
nkeynes@221 | 612 | }
|
nkeynes@221 | 613 |
|
nkeynes@221 | 614 | }
|
nkeynes@221 | 615 |
|
nkeynes@221 | 616 |
|
nkeynes@219 | 617 | void render_backplane( uint32_t *polygon, uint32_t width, uint32_t height, uint32_t mode ) {
|
nkeynes@221 | 618 | struct vertex_all vertex[3];
|
nkeynes@221 | 619 | int screen_vertexes[4] = {0,1,2,3};
|
nkeynes@221 | 620 | struct bkg_scene scene;
|
nkeynes@221 | 621 | int i,j,k, num_vertexes;
|
nkeynes@219 | 622 |
|
nkeynes@221 | 623 | parse_vertexes(polygon, 3, vertex);
|
nkeynes@219 | 624 | render_set_context(polygon, 0);
|
nkeynes@221 | 625 | glDisable(GL_CULL_FACE);
|
nkeynes@221 | 626 | glDisable(GL_DEPTH_TEST);
|
nkeynes@221 | 627 | glBlendFunc(GL_ONE, GL_ZERO); /* For now, just disable alpha blending on the bkg */
|
nkeynes@221 | 628 | bkg_compute_scene(vertex, width, height, &scene);
|
nkeynes@221 | 629 | bkg_render_region(&scene, 0, screen_vertexes, 4, *polygon);
|
nkeynes@219 | 630 | }
|