--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/pvr2/gl_sl.c	Mon Feb 18 09:21:43 2008 +0000
@@ -0,0 +1,223 @@
+/**
+ * $Id$
+ *
+ * GLSL shader loader/unloader. Current version assumes there's exactly
+ * 1 shader program that's used globally. This may turn out not to be the
+ * most efficient approach.
+ *
+ * Copyright (c) 2007 Nathan Keynes.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define GL_GLEXT_PROTOTYPES 1
+
+#include "lxdream.h"
+#include "display.h"
+#include "pvr2/glutil.h"
+
+#define MAX_ERROR_BUF 4096
+
+gboolean glsl_is_supported()
+{
+    return isGLExtensionSupported("GL_ARB_fragment_shader") &&
+	isGLExtensionSupported("GL_ARB_vertex_shader") &&
+	isGLExtensionSupported("GL_ARB_shading_language_100");
+}
+
+#ifdef GL_ARB_shader_objects
+static GLhandleARB glsl_program = 0, glsl_vert_shader = 0, glsl_frag_shader = 0;
+
+void glsl_print_error( char *msg, GLhandleARB obj )
+{
+    char buf[MAX_ERROR_BUF];
+    GLsizei length;
+    glGetInfoLogARB( obj, sizeof(buf), &length, buf );
+    ERROR( "%s: %s", msg, buf );
+}
+
+gboolean glsl_check_shader_error( char *msg, GLhandleARB obj )
+{
+    GLint value;
+
+    glGetObjectParameterivARB(obj, GL_OBJECT_COMPILE_STATUS_ARB, &value);
+    if( value == 0 ) {
+	glsl_print_error(msg, obj);
+	return FALSE;
+    }
+    return TRUE;
+}
+
+gboolean glsl_check_program_error( char *msg, GLhandleARB obj )
+{
+    if( glGetError() != GL_NO_ERROR ) {
+	glsl_print_error(msg, obj);
+    }
+    return TRUE;
+}
+
+
+gboolean glsl_load_shaders( const char *vertex_src, const char *fragment_src )
+{
+    gboolean vsok = TRUE, fsok = TRUE, pok = FALSE;
+
+    if( vertex_src == NULL && fragment_src == NULL ) {
+	return TRUE; // nothing to do
+    }
+
+    glsl_program = glCreateProgramObjectARB();
+
+    if( vertex_src != NULL ) {
+	glsl_vert_shader = glCreateShaderObjectARB(GL_VERTEX_SHADER_ARB);
+	glShaderSourceARB( glsl_vert_shader, 1, &vertex_src, NULL );
+	glCompileShaderARB(glsl_vert_shader);
+	vsok = glsl_check_shader_error("Failed to compile vertex shader", glsl_vert_shader);
+    }
+    if( fragment_src != NULL ) {
+	glsl_frag_shader = glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
+	glShaderSourceARB( glsl_frag_shader, 1, &fragment_src, NULL );
+	glCompileShaderARB(glsl_frag_shader);
+	fsok = glsl_check_shader_error("Failed to compile fragment shader", glsl_frag_shader);
+    }
+
+    if( vsok && fsok ) {
+	if( vertex_src != NULL ) {
+	    glAttachObjectARB(glsl_program, glsl_vert_shader);
+	}
+	if( fragment_src != NULL ) {
+	    glAttachObjectARB(glsl_program, glsl_frag_shader);
+	}
+	glLinkProgramARB(glsl_program);
+	pok = glsl_check_program_error( "Failed to link shader program", glsl_program );
+    }
+    if( pok ) {
+	glUseProgramObjectARB(glsl_program);
+	pok = glsl_check_program_error( "Failed to apply shader program", glsl_program );
+    } else {
+	glsl_unload_shaders();
+    }
+    return pok;
+}
+
+void glsl_enable_shader(gboolean en)
+{
+    if( glsl_program != 0 ) {
+	if( en ) {
+	    glUseProgramObjectARB(glsl_program);
+	} else {
+	    glUseProgramObjectARB(0);
+	}
+    }
+}
+
+void glsl_unload_shaders(void)
+{
+    glUseProgramObjectARB(0);
+    glDetachObjectARB(glsl_program, glsl_vert_shader);
+    glDetachObjectARB(glsl_program, glsl_frag_shader);
+    glDeleteObjectARB(glsl_program);
+    glDeleteObjectARB(glsl_vert_shader);
+    glDeleteObjectARB(glsl_frag_shader);
+}
+
+#else
+static GLuint glsl_program = 0, glsl_vert_shader = 0, glsl_frag_shader = 0;
+
+gboolean glsl_check_shader_error( char *msg, GLuint shader )
+{
+    GLint value;
+
+    glGetShaderiv( shader, GL_COMPILE_STATUS, &value );
+    if( value == 0 ) {
+	char buf[MAX_ERROR_BUF];
+	GLsizei length;
+	glGetShaderInfoLog( shader, sizeof(buf), &length, buf );
+	ERROR( "%s: %s", msg, buf );
+	return FALSE;
+    }
+    return TRUE;
+}
+gboolean glsl_check_program_error( char *msg, GLuint program )
+{
+    if( glGetError() != GL_NO_ERROR ) {
+	char buf[MAX_ERROR_BUF];
+	GLsizei length;
+	glGetProgramInfoLog( program, sizeof(buf), &length, buf );
+	ERROR( "%s: %s", msg, buf );
+	return FALSE;
+    }
+    return TRUE;
+}
+
+gboolean glsl_load_shaders( const char *vertex_src, const char *fragment_src )
+{
+    gboolean vsok = TRUE, fsok = TRUE, pok = FALSE;
+
+    if( vertex_src == NULL && fragment_src == NULL ) {
+	return TRUE;
+    }
+
+    glsl_program = glCreateProgram();
+
+    if( vertex_src != NULL ) {
+	glsl_vert_shader = glCreateShader(GL_VERTEX_SHADER);
+	glShaderSource( glsl_vert_shader, 1, &vertex_src, NULL );
+	glCompileShader(glsl_vert_shader);
+	vsok = glsl_check_shader_error( "Failed to compile vertex shader", glsl_vert_shader );
+    }
+    if( fragment_src != NULL ) {
+	glsl_frag_shader = glCreateShader(GL_FRAGMENT_SHADER);
+	glShaderSource( glsl_frag_shader, 1, &fragment_src, NULL );
+	glCompileShader(glsl_frag_shader);
+	fsok = glsl_check_shader_error( "Failed to compile fragment shader", glsl_frag_shader );
+    }
+
+    if( vsok && fsok ) {
+	if( vertex_src != NULL ) {
+	    glAttachShader(glsl_program, glsl_vert_shader);
+	}
+	if( fragment_src != NULL ) {
+	    glAttachShader(glsl_program, glsl_frag_shader);
+	}
+	glLinkProgram(glsl_program);
+	pok = glsl_check_program_error( "Failed to link shader program", glsl_program );
+    }
+
+    if( pok ) {
+	glUseProgram(glsl_program);
+    } else {
+	glsl_unload_shaders();
+    }
+    return pok;
+}
+
+
+void glsl_enable_shader(gboolean en)
+{
+    if( glsl_program != 0 ) {
+	if( en ) {
+	    glUseProgram(glsl_program);
+	} else {
+	    glUseProgram(0);
+	}
+    }
+}
+
+void glsl_unload_shaders(void)
+{
+    glUseProgram(0);
+    glDetachShader(glsl_program, glsl_vert_shader);
+    glDetachShader(glsl_program, glsl_frag_shader);
+    glDeleteProgram(glsl_program);
+    glDeleteShader(glsl_vert_shader);
+    glDeleteShader(glsl_frag_shader);
+}
+#endif