4 * PVR2 background renderer.
6 * Yes, it uses the same basic data structure. Yes, it needs to be handled
7 * completely differently.
9 * PVR2 backgrounds are defined as a set of three fully specified vertexes,
10 * stored in compiled-vertex format. The vertexes form a triangle which is
11 * rendered in the normal fashion. Points outside the triangle are rendered
12 * by extrapolating from the gradients established by the triangle, giving
13 * an overall smooth gradient across the background. Points are colour-clamped
14 * prior to output to the buffer.
16 * As a special case, if all three points lie on the same line (or are the same
17 * point, the third point is used by itself to define the entire buffer (ie
18 * effectively a solid colour).
20 * Note: this would be really simple if GL did unclamped colour interpolation
21 * but it doesn't (portably), which makes this roughly 2 orders of magnitude
22 * more complicated than it otherwise would be.
24 * Copyright (c) 2005 Nathan Keynes.
26 * This program is free software; you can redistribute it and/or modify
27 * it under the terms of the GNU General Public License as published by
28 * the Free Software Foundation; either version 2 of the License, or
29 * (at your option) any later version.
31 * This program is distributed in the hope that it will be useful,
32 * but WITHOUT ANY WARRANTY; without even the implied warranty of
33 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
34 * GNU General Public License for more details.
39 #include "pvr2/pvr2.h"
40 #include "pvr2/pvr2mmio.h"
43 #define MAX_CLAMP_LINES 8
44 #define MAX_VERTEXES 256
45 #define MAX_REGIONS 256
47 #define FARGB_A(x) (((float)(((x)>>24)+1))/256.0)
48 #define FARGB_R(x) (((float)((((x)>>16)&0xFF)+1))/256.0)
49 #define FARGB_G(x) (((float)((((x)>>8)&0xFF)+1))/256.0)
50 #define FARGB_B(x) (((float)(((x)&0xFF)+1))/256.0)
53 * Convert a half-float (16-bit) FP number to a regular 32-bit float.
54 * Source is 1-bit sign, 5-bit exponent, 10-bit mantissa.
55 * TODO: Check the correctness of this.
57 static float halftofloat( uint16_t half )
63 /* int e = ((half & 0x7C00) >> 10) - 15 + 127;
65 temp.i = ((half & 0x8000) << 16) | (e << 23) |
66 ((half & 0x03FF) << 13); */
67 temp.i = ((uint32_t)half)<<16;
71 void render_unpack_vertexes( struct vertex_unpacked *out, uint32_t poly1,
72 uint32_t *vertexes, int num_vertexes,
73 int vertex_size, int render_mode )
76 if( render_mode == RENDER_FULLMOD ) {
77 m = (vertex_size - 3)/2;
80 for( i=0; i<num_vertexes; i++ ) {
81 float *vertexf = (float *)vertexes;
83 out[i].x = vertexf[0];
84 out[i].y = vertexf[1];
85 out[i].z = vertexf[2];
86 if( POLY1_TEXTURED(poly1) ) {
87 if( POLY1_UV16(poly1) ) {
88 out[i].u = halftofloat(vertexes[k]>>16);
89 out[i].v = halftofloat(vertexes[k]);
92 out[i].u = vertexf[k];
93 out[i].v = vertexf[k+1];
100 uint32_t argb = vertexes[k++];
101 out[i].rgba[0] = FARGB_R(argb);
102 out[i].rgba[1] = FARGB_G(argb);
103 out[i].rgba[2] = FARGB_B(argb);
104 out[i].rgba[3] = FARGB_A(argb);
105 if( POLY1_SPECULAR(poly1) ) {
106 uint32_t offset = vertexes[k++];
107 out[i].offset_rgba[0] = FARGB_R(offset);
108 out[i].offset_rgba[1] = FARGB_G(offset);
109 out[i].offset_rgba[2] = FARGB_B(offset);
110 out[i].offset_rgba[3] = FARGB_A(offset);
112 vertexes += vertex_size;
117 * Compute the line where k = target_k, (where k is normally one of
118 * r,g,b,a, or z) and determines the points at which the line intersects
119 * the viewport (0,0,width,height).
121 * @param center_x the x value for the center position
122 * @param center_y the y value for the center position
123 * @param center_k the k value for the center position
124 * @param width Width of the viewport (ie 640)
125 * @param height Height of the viewport (ie 480)
126 * @param target_k determine the line where k = this value, ie 1.0
128 * @param target Array to write the resultant x,y pairs to (note this
129 * function only sets x and y values).
130 * @return number of vertexes written to the target.
132 static int compute_colour_line( float center_x, float center_y, float center_k,
133 int width, int height, float target_k,
134 float detxy, float detxk, float detyk,
135 struct vertex_unpacked *target ) {
137 float tmpk = (target_k - center_k) * detxy;
142 x0 = (tmpk - ((0-center_y)*detxk))/detyk + center_x; /* x where y=0 */
143 if( x0 >= 0.0 && x0 <= width ) {
144 target[num_points].x = x0;
145 target[num_points].y = 0.0;
149 x1 = (tmpk - ((height-center_y)*detxk))/detyk + center_x; /* x where y=height */
150 if( x1 >= 0.0 && x1 <= width ) {
151 target[num_points].x = x1;
152 target[num_points].y = height;
158 if( x0 != 0.0 && x1 != 0.0 ) { /* If x0 == 0 or x1 == 0, then we already have this one */
159 float y0 = (tmpk - ((0-center_x)*detyk))/detxk + center_y; /* y where x=0 */
160 if( y0 >= 0.0 && y0 <= height ) {
161 target[num_points].x = 0.0;
162 target[num_points].y = y0;
167 if( x0 != width && x1 != width ) {
168 float y1 = (tmpk - ((width-center_x)*detyk))/detxk + center_y; /* y where x=width */
169 if( y1 >= 0.0 && y1 <= height ) {
170 target[num_points].x = width;
171 target[num_points].y = y1;
177 if( num_points == 0 || num_points == 2 ) {
178 /* 0 = no points - line doesn't pass through the viewport */
179 /* 2 = normal case - got 2 endpoints */
182 ERROR( "compute_colour_line got bad number of points: %d", num_points );
188 * A region describes a portion of the screen, possibly subdivided by a line.
189 * if region_left and region_right are -1, this is a terminal region that can
190 * be rendered directly. Otherwise region_left and region_right refer two
191 * sub-regions that are separated by the line segment vertex1-vertex2.
194 /* Vertexes marking the line segment that splits this region */
197 /* Index of the left sub-region */
199 /* Index of the right sub-region */
204 * Convenience structure to bundle together the vertex and region data.
209 struct vertex_unpacked vertexes[MAX_VERTEXES];
210 struct bkg_region regions[MAX_REGIONS];
214 * Constants returned by compute_line_intersection. Note that for these purposes,
215 * "Left" means the point(s) result in a negative value in the line equation, while
216 * "Right" means the points(s) result in a positive value in the line equation. The
217 * exact meaning isn't particularly important though, as long as we're consistent
218 * throughout this process
220 #define LINE_COLLINEAR 0 /* The line segments are part of the same line */
221 #define LINE_SIDE_LEFT 1 /* The second line is entirely to the "left" of the first line */
222 #define LINE_SIDE_RIGHT 2 /* The second line is entirely to the "right" of the first line */
223 #define LINE_INTERSECT_FROM_LEFT 3 /* The lines intersect, and (x3,y3) is to the "left" of the first line */
224 #define LINE_INTERSECT_FROM_RIGHT 4 /* The lines intersect, and (x3,y3) is to the "right" of the first line */
225 #define LINE_SKEW 5 /* The line segments neither intersect nor do any of the above apply (should never happen here) */
228 * Compute the intersection of two line segments, where
229 * (x1,y1)-(x2,y2) defines the target segment, and
230 * (x3,y3)-(x4,y4) defines the line intersecting it.
232 * Based off work by Mukesh Prasad (http://www.acm.org/pubs/tog/GraphicsGems/index.html)
234 * @return one of the above LINE_* constants
236 static int compute_line_intersection( float x1, float y1, /* First line segment */
238 float x3, float y3, /* Second line segment */
240 float *x, float *y ) /* Output value: */
242 float a1, a2, b1, b2, c1, c2; /* Coefficients of line eqns. */
243 float r1, r2, r3, r4; /* test values */
244 float denom; /* Intermediate values */
246 /* Compute a1, b1, c1, where line joining points 1 and 2
247 * is "a1 x + b1 y + c1 = 0".
252 c1 = x2 * y1 - x1 * y2;
254 /* Compute r3 and r4. */
256 r3 = a1 * x3 + b1 * y3 + c1;
257 r4 = a1 * x4 + b1 * y4 + c1;
259 /* Check signs of r3 and r4. If both point 3 and point 4 lie on
260 * same side of line 1, the line segments do not intersect.
263 if( r3 == 0 && r4 == 0 ) {
264 return LINE_COLLINEAR;
265 } else if( r3 <= 0 && r4 <= 0 ) {
266 return LINE_SIDE_LEFT;
267 } else if( r3 >= 0 && r4 >= 0 ) {
268 return LINE_SIDE_RIGHT;
271 /* Compute a2, b2, c2 */
275 c2 = x4 * y3 - x3 * y4;
277 /* Compute r1 and r2 */
279 r1 = a2 * x1 + b2 * y1 + c2;
280 r2 = a2 * x2 + b2 * y2 + c2;
282 /* Check signs of r1 and r2. If both point 1 and point 2 lie
283 * on same side of second line segment, the line segments do
287 if ( r1 != 0 && r2 != 0 &&
288 signbit(r1) == signbit(r2) ) {
289 return LINE_SKEW; /* Should never happen */
292 /* Cmpute intersection point.
294 denom = a1 * b2 - a2 * b1;
296 return LINE_COLLINEAR; /* Should never get to this point either */
298 *x = (b1 * c2 - b2 * c1) / denom;
299 *y = (a2 * c1 - a1 * c2) / denom;
301 if( r3 <= 0 && r4 >= 0 ) {
302 return LINE_INTERSECT_FROM_LEFT;
304 return LINE_INTERSECT_FROM_RIGHT;
309 * Given a set of vertexes and a line segment to use to split them, generates
310 * two sets of vertexes representing the polygon on either side of the line
311 * segment. This method preserves the winding direction of the input vertexes.
313 static void compute_subregions( struct bkg_scene *scene,
314 int splitv1, int splitv2,
315 int *vertex_in, int num_vertex_in,
316 int *left_vertex_out, int *num_left_vertex_out,
317 int *right_vertex_out, int *num_right_vertex_out )
319 float x1 = scene->vertexes[splitv1].x;
320 float y1 = scene->vertexes[splitv1].y;
321 float x2 = scene->vertexes[splitv2].x;
322 float y2 = scene->vertexes[splitv2].y;
326 float c1 = x2 * y1 - x1 * y2;
329 *num_left_vertex_out = 0;
330 *num_right_vertex_out = 0;
332 for( i=0; i<num_vertex_in; i++ ) {
333 struct vertex_unpacked *vertex = &scene->vertexes[vertex_in[i]];
334 float r = a1 * vertex->x + b1 * vertex->y + c1;
337 /* cross-point. add the split vertexes */
338 int v1 = vertex_in[i-1];
339 int v2 = vertex_in[i];
340 /* Determine which point is closer to the line. Strictly speaking
341 * one of them must be ON the line, but this way allows for floating
342 * point inaccuracies.
344 float a2 = scene->vertexes[v2].y - scene->vertexes[v1].y;
345 float b2 = scene->vertexes[v1].x - scene->vertexes[v2].x;
346 float c2 = scene->vertexes[v2].x * scene->vertexes[v1].y -
347 scene->vertexes[v1].x * scene->vertexes[v2].y;
348 float r1 = a2 * x1 + b2 * y1 + c2;
349 float r2 = a2 * x2 + b2 * y2 + c2;
350 if( fabsf(r1) > fabs(r2) ) {
355 right_vertex_out[(*num_right_vertex_out)++] = splitv1;
356 right_vertex_out[(*num_right_vertex_out)++] = splitv2;
357 left_vertex_out[(*num_left_vertex_out)++] = splitv2;
358 left_vertex_out[(*num_left_vertex_out)++] = splitv1;
360 } else if( last != 2 ) {
363 left_vertex_out[(*num_left_vertex_out)++] = vertex_in[i];
366 /* cross-point. add the split vertexes */
367 int v1 = vertex_in[i-1];
368 int v2 = vertex_in[i];
369 /* Determine which point is closer to the line. Strictly speaking
370 * one of them must be ON the line, but this way allows for floating
371 * point inaccuracies.
373 float a2 = scene->vertexes[v2].y - scene->vertexes[v1].y;
374 float b2 = scene->vertexes[v1].x - scene->vertexes[v2].x;
375 float c2 = scene->vertexes[v2].x * scene->vertexes[v1].y -
376 scene->vertexes[v1].x * scene->vertexes[v2].y;
377 float r1 = a2 * x1 + b2 * y1 + c2;
378 float r2 = a2 * x2 + b2 * y2 + c2;
379 if( fabsf(r1) > fabs(r2) ) {
384 left_vertex_out[(*num_left_vertex_out)++] = splitv1;
385 left_vertex_out[(*num_left_vertex_out)++] = splitv2;
386 right_vertex_out[(*num_right_vertex_out)++] = splitv2;
387 right_vertex_out[(*num_right_vertex_out)++] = splitv1;
389 } else if( last != 2 ) {
392 right_vertex_out[(*num_right_vertex_out)++] = vertex_in[i];
398 * Subdivide the region tree by splitting it along a given line.
400 * @param scene current bkg scene data
401 * @param region current region under examination
402 * @param vertex1 first vertex of the new line segment
403 * @param vertex2 second vertex of the new line segment
405 static void bkg_region_subdivide( struct bkg_scene *scene, int region, int vertex1, int vertex2 ) {
406 struct bkg_region *this_region = &scene->regions[region];
408 if( scene->regions[region].region_left == -1 || scene->regions[region].region_right == -1 ) {
409 /* Reached the end of the tree. Setup new left+right regions */
410 int i = scene->num_regions;
411 scene->regions[i].region_left = scene->regions[i].region_right = -1;
412 scene->regions[i+1].region_left = scene->regions[i+1].region_right = -1;
413 this_region->region_left = i;
414 this_region->region_right = i+1;
415 this_region->vertex1 = vertex1;
416 this_region->vertex2 = vertex2;
417 scene->num_regions += 2;
420 int thisv1 = this_region->vertex1;
421 int thisv2 = this_region->vertex2;
424 compute_line_intersection( scene->vertexes[thisv1].x, scene->vertexes[thisv1].y,
425 scene->vertexes[thisv2].x, scene->vertexes[thisv2].y,
426 scene->vertexes[vertex1].x, scene->vertexes[vertex1].y,
427 scene->vertexes[vertex2].x, scene->vertexes[vertex2].y,
430 case LINE_INTERSECT_FROM_LEFT:
431 /* if new line segment intersects our current line segment,
432 * subdivide the segment (add a new vertex) and recurse on both
435 /* Compute split-point vertex */
436 vertex3 = scene->num_vertexes++;
437 scene->vertexes[vertex3].x = x;
438 scene->vertexes[vertex3].y = y;
440 bkg_region_subdivide( scene, scene->regions[region].region_left, vertex1,vertex3 );
441 bkg_region_subdivide( scene, scene->regions[region].region_right, vertex3, vertex2 );
443 case LINE_INTERSECT_FROM_RIGHT:
444 /* Same except line runs in the opposite direction */
445 vertex3 = scene->num_vertexes++;
446 scene->vertexes[vertex3].x = x;
447 scene->vertexes[vertex3].y = y;
449 bkg_region_subdivide( scene, scene->regions[region].region_left, vertex2,vertex3 );
450 bkg_region_subdivide( scene, scene->regions[region].region_right, vertex3, vertex1 );
454 /* Collinear - ignore */
457 /* else if line segment passes through the left sub-region alone,
460 bkg_region_subdivide( scene, scene->regions[region].region_left, vertex1, vertex2 );
462 case LINE_SIDE_RIGHT:
463 /* Otherwise line segment passes through the right sub-region alone,
466 bkg_region_subdivide( scene, scene->regions[region].region_right, vertex1, vertex2 );
475 * Compute the values for an array of vertexes, given x,y for each
476 * vertex and the base 3-vertex triple used to define the background
477 * plane. Essentially the base vertexes are used to find the
478 * plane equation for each of z,a,r,g,b,etc, which is then solved for
479 * each of the required compute vertexes (normally the corner points).
481 * @param base The 3 vertexes supplied as the background definition
482 * @param compute An array of vertexes to compute. x and y must be
483 * preset, other values are computed.
485 static void bkg_compute_scene( struct vertex_unpacked *base, int width, int height,
486 struct bkg_scene *scene )
488 struct vertex_unpacked center;
489 struct vertex_unpacked diff0, diff1;
492 center.x = base[1].x;
493 center.y = base[1].y;
494 center.z = base[1].z;
495 center.u = base[1].u;
496 center.v = base[1].v;
497 diff0.x = base[0].x - center.x;
498 diff0.y = base[0].y - center.y;
499 diff0.z = base[0].z - center.z;
500 diff1.x = base[2].x - center.x;
501 diff1.y = base[2].y - center.y;
502 diff1.z = base[2].z - center.z;
504 float detxy = ((diff1.y) * (diff0.x)) - ((diff0.y) * (diff1.x));
506 /* Corner points first */
507 scene->vertexes[0].x = 0.0;
508 scene->vertexes[0].y = 0.0;
509 scene->vertexes[1].x = width;
510 scene->vertexes[1].y = 0.0;
511 scene->vertexes[2].x = width;
512 scene->vertexes[2].y = height;
513 scene->vertexes[3].x = 0.0;
514 scene->vertexes[3].y = height;
515 scene->regions[0].region_left = -1;
516 scene->regions[0].region_right = -1;
517 scene->num_vertexes = 4;
518 scene->num_regions = 1;
521 /* The points lie on a single line - no plane for you. Use the values
522 * from the 3rd point for the whole screen.
524 for( i=0; i<4; i++ ) {
525 scene->vertexes[i].rgba[0] = base[2].rgba[0];
526 scene->vertexes[i].rgba[1] = base[2].rgba[1];
527 scene->vertexes[i].rgba[2] = base[2].rgba[2];
528 scene->vertexes[i].rgba[3] = base[2].rgba[3];
529 scene->vertexes[i].z = base[2].z;
530 scene->vertexes[i].u = base[2].u;
531 scene->vertexes[i].v = base[2].v;
534 /* Compute the colour values at each corner */
535 center.rgba[0] = base[1].rgba[0];
536 center.rgba[1] = base[1].rgba[1];
537 center.rgba[2] = base[1].rgba[2];
538 center.rgba[3] = base[1].rgba[3];
539 diff0.rgba[0] = base[0].rgba[0] - center.rgba[0];
540 diff0.rgba[1] = base[0].rgba[1] - center.rgba[1];
541 diff0.rgba[2] = base[0].rgba[2] - center.rgba[2];
542 diff0.rgba[3] = base[0].rgba[3] - center.rgba[3];
543 diff0.u = base[0].u - center.u;
544 diff0.v = base[0].v - center.v;
545 diff1.rgba[0] = base[2].rgba[0] - center.rgba[0];
546 diff1.rgba[1] = base[2].rgba[1] - center.rgba[1];
547 diff1.rgba[2] = base[2].rgba[2] - center.rgba[2];
548 diff1.rgba[3] = base[2].rgba[3] - center.rgba[3];
549 diff1.u = base[2].u - center.u;
550 diff1.v = base[2].v - center.v;
551 for( i=0; i<4; i++ ) {
552 float t = ((scene->vertexes[i].x - center.x) * diff1.y -
553 (scene->vertexes[i].y - center.y) * diff1.x) / detxy;
554 float s = ((scene->vertexes[i].y - center.y) * diff0.x -
555 (scene->vertexes[i].x - center.x) * diff0.y) / detxy;
556 scene->vertexes[i].z = center.z + (t*diff0.z) + (s*diff1.z);
557 scene->vertexes[i].rgba[0] = center.rgba[0] + (t*diff0.rgba[0]) + (s*diff1.rgba[0]);
558 scene->vertexes[i].rgba[1] = center.rgba[1] + (t*diff0.rgba[1]) + (s*diff1.rgba[1]);
559 scene->vertexes[i].rgba[2] = center.rgba[2] + (t*diff0.rgba[2]) + (s*diff1.rgba[2]);
560 scene->vertexes[i].rgba[3] = center.rgba[3] + (t*diff0.rgba[3]) + (s*diff1.rgba[3]);
561 scene->vertexes[i].u = center.u + (t*diff0.u) + (s*diff1.u);
562 scene->vertexes[i].v = center.v + (t*diff0.v) + (s*diff1.v);
565 /* Check for values > 1.0 | < 0.0 */
566 for( k=0; k<4; k++ ) {
567 float detyk = ((diff1.y) * (diff0.rgba[k])) - ((diff0.y)*(diff1.rgba[k]));
568 float detxk = ((diff0.x) * (diff1.rgba[k])) - ((diff1.x)*(diff0.rgba[k]));
569 if( scene->vertexes[0].rgba[k] > 1.0 || scene->vertexes[1].rgba[k] > 1.0 ||
570 scene->vertexes[2].rgba[k] > 1.0 || scene->vertexes[3].rgba[k] > 1.0 ) {
571 int v1 = scene->num_vertexes;
572 scene->num_vertexes += compute_colour_line(center.x, center.y, center.rgba[k],
575 scene->vertexes+scene->num_vertexes );
576 if( scene->num_vertexes != v1 ) {
577 bkg_region_subdivide( scene, 0, v1, v1+1 );
581 if( scene->vertexes[0].rgba[k] < 0.0 || scene->vertexes[1].rgba[k] < 0.0 ||
582 scene->vertexes[2].rgba[k] < 0.0 || scene->vertexes[3].rgba[k] < 0.0 ) {
583 int v1 = scene->num_vertexes;
584 scene->num_vertexes += compute_colour_line(center.x, center.y, center.rgba[k],
587 scene->vertexes+scene->num_vertexes );
588 if( scene->num_vertexes != v1 ) {
589 bkg_region_subdivide( scene, 0, v1, v1+1 );
595 /* Finally compute the colour values for all vertexes
596 * (excluding the 4 we did upfront) */
597 for( i=4; i<scene->num_vertexes; i++ ) {
598 float t = ((scene->vertexes[i].x - center.x) * diff1.y -
599 (scene->vertexes[i].y - center.y) * diff1.x) / detxy;
600 float s = ((scene->vertexes[i].y - center.y) * diff0.x -
601 (scene->vertexes[i].x - center.x) * diff0.y) / detxy;
602 scene->vertexes[i].z = center.z + (t*diff0.z) + (s*diff1.z);
603 scene->vertexes[i].rgba[0] = center.rgba[0] + (t*diff0.rgba[0]) + (s*diff1.rgba[0]);
604 scene->vertexes[i].rgba[1] = center.rgba[1] + (t*diff0.rgba[1]) + (s*diff1.rgba[1]);
605 scene->vertexes[i].rgba[2] = center.rgba[2] + (t*diff0.rgba[2]) + (s*diff1.rgba[2]);
606 scene->vertexes[i].rgba[3] = center.rgba[3] + (t*diff0.rgba[3]) + (s*diff1.rgba[3]);
607 scene->vertexes[i].u = center.u + (t*diff0.u) + (s*diff1.u);
608 scene->vertexes[i].v = center.v + (t*diff0.v) + (s*diff1.v);
614 * Render a bkg_region.
615 * @param scene the background scene data
616 * @param region the region to render
617 * @param vertexes the vertexes surrounding the region
618 * @param num_vertexes the number of vertexes in the vertex array
620 void bkg_render_region( struct bkg_scene *scene, int region, int *vertexes, int num_vertexes,
623 if( scene->regions[region].region_left == -1 && scene->regions[region].region_right == -1 ) {
624 /* Leaf node - render the points as given */
627 for( i=0; i<num_vertexes; i++ ) {
629 glColor4fv(scene->vertexes[k].rgba);
630 if( POLY1_TEXTURED(poly1) ) {
631 glTexCoord2f(scene->vertexes[k].u, scene->vertexes[k].v);
633 glVertex3f(scene->vertexes[k].x, scene->vertexes[k].y, scene->vertexes[k].z);
637 /* split the region into left and right regions */
638 int left_vertexes[num_vertexes+1];
639 int right_vertexes[num_vertexes+1];
642 struct bkg_region *reg = &scene->regions[region];
643 compute_subregions( scene, reg->vertex1, reg->vertex2, vertexes, num_vertexes,
644 left_vertexes, &num_left, right_vertexes, &num_right );
645 bkg_render_region( scene, reg->region_left, left_vertexes, num_left, poly1 );
646 bkg_render_region( scene, reg->region_right, right_vertexes, num_right, poly1 );
652 void render_backplane( uint32_t *polygon, uint32_t width, uint32_t height, uint32_t mode ) {
653 struct vertex_unpacked vertex[3];
654 int screen_vertexes[4] = {0,1,2,3};
655 struct bkg_scene scene;
656 int vertex_length = (mode >> 24) & 0x07;
657 int cheap_shadow = MMIO_READ( PVR2, RENDER_SHADOW ) & 0x100;
658 int is_modified = mode & 0x08000000;
659 int context_length = 3;
660 if( is_modified && !cheap_shadow ) {
665 context_length += (mode & 0x07) * vertex_length;
668 render_unpack_vertexes( vertex, *polygon, polygon+context_length, 3, vertex_length,
670 bkg_compute_scene(vertex, width, height, &scene);
671 render_set_context(polygon, RENDER_NORMAL);
672 glDisable(GL_CULL_FACE);
673 glDisable(GL_DEPTH_TEST);
674 glBlendFunc(GL_ONE, GL_ZERO); /* For now, just disable alpha blending on the bkg */
675 bkg_render_region(&scene, 0, screen_vertexes, 4, *polygon);
676 glEnable(GL_CULL_FACE);
677 glEnable(GL_DEPTH_TEST);
.