src/graphics/grgl2shader.cpp

   1 /*
   2  * Copyright (C) Volition, Inc. 1999.  All rights reserved.
   3  *
   4  * All source code herein is the property of Volition, Inc. You may not sell
   5  * or otherwise commercially exploit the source or things you created based on
   6  * the source.
   7  */
   8
   9 #include "SDL_opengles2.h"
  10
  11 #include "pstypes.h"
  12 #include "gropengl.h"
  13 #include "gropenglinternal.h"
  14 #include "grgl2.h"
  15
  16
  17 GLuint basicTexture = 0;
  18
  19
  20 static const char vert_src[] =
  21         "uniform mat4 vOrtho;\n"
  22         "attribute vec4 vPosition;\n"
  23         "attribute vec4 vColor;\n"
  24         "attribute vec2 vTexCoord;\n"
  25         "varying vec4 colorVar;\n"
  26         "varying vec2 texCoordVar;\n"
  27         "void main()\n"
  28         "{\n"
  29         "       gl_Position = vOrtho * vPosition;\n"
  30         "       colorVar = vColor;\n"
  31         "       texCoordVar = vTexCoord;\n"
  32         "}\n";
  33
  34 static const char frag_src[] =
  35         "precision mediump float;\n"
  36         "uniform sampler2D texture;\n"
  37         "varying vec4 colorVar;\n"
  38         "varying vec2 texCoordVar;\n"
  39         "void main()\n"
  40         "{\n"
  41         "       gl_FragColor = colorVar * texture2D(texture, texCoordVar);\n"
  42         "}\n";
  43
  44
  45 static GLuint opengl2_create_shader(const char *src, GLenum type)
  46 {
  47         GLuint shader;
  48         GLint compiled;
  49
  50         shader = glCreateShader(type);
  51
  52         if ( !shader ) {
  53                 return 0;
  54         }
  55
  56         glShaderSource(shader, 1, &src, NULL);
  57
  58         glCompileShader(shader);
  59
  60         glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
  61
  62         if ( !compiled ) {
  63                 GLint len = 0;
  64
  65                 glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &len);
  66
  67                 if (len > 1) {
  68                         char *log = (char *) malloc(sizeof(char) * len);
  69
  70                         glGetShaderInfoLog(shader, len, NULL, log);
  71                         nprintf(("OpenGL", "Error compiling shader:\n%s\n", log));
  72
  73                         free(log);
  74                 }
  75
  76                 glDeleteShader(shader);
  77
  78                 return 0;
  79         }
  80
  81         return shader;
  82 }
  83 /*
  84 static GLuint opengl2_create_program(GLuint vert, GLuint frag)
  85 {
  86         GLuint program;
  87         GLint linked;
  88
  89         program = glCreateProgram();
  90
  91         if ( !program ) {
  92                 return 0;
  93         }
  94
  95         glAttachShader(program, vert);
  96         glAttachShader(program, frag);
  97
  98         glLinkProgram(program);
  99
 100         glGetProgramiv(program, GL_LINK_STATUS, &linked);
 101
 102         if ( !linked ) {
 103                 GLint len = 0;
 104
 105                 glGetProgramiv(basicTexture, GL_INFO_LOG_LENGTH, &len);
 106
 107                 if (len > 1) {
 108                         char *log = (char *) malloc(sizeof(char) * len);
 109
 110                         glGetProgramInfoLog(basicTexture, len, NULL, log);
 111                         nprintf(("OpenGL", "Error linking program:\n%s\n", log));
 112
 113                         free(log);
 114                 }
 115
 116                 glDeleteProgram(basicTexture);
 117
 118                 return 0;
 119         }
 120
 121         return program;
 122 }
 123 */
 124 int opengl2_shader_init()
 125 {
 126         GLint linked;
 127
 128         GLuint vert_shader = opengl2_create_shader(vert_src, GL_VERTEX_SHADER);
 129         GLuint frag_shader = opengl2_create_shader(frag_src, GL_FRAGMENT_SHADER);
 130
 131         basicTexture = glCreateProgram();
 132
 133         if ( !basicTexture ) {
 134                 return 0;
 135         }
 136
 137         glAttachShader(basicTexture, vert_shader);
 138         glAttachShader(basicTexture, frag_shader);
 139
 140         glBindAttribLocation(basicTexture, 1, "vPosition");
 141         glBindAttribLocation(basicTexture, 2, "vColor");
 142         glBindAttribLocation(basicTexture, 3, "vTexCoord");
 143
 144         glLinkProgram(basicTexture);
 145
 146         glGetProgramiv(basicTexture, GL_LINK_STATUS, &linked);
 147
 148         if ( !linked ) {
 149                 GLint len = 0;
 150
 151                 glGetProgramiv(basicTexture, GL_INFO_LOG_LENGTH, &len);
 152
 153                 if (len > 1) {
 154                         char *log = (char *) malloc(sizeof(char) * len);
 155
 156                         glGetProgramInfoLog(basicTexture, len, NULL, log);
 157                         nprintf(("OpenGL", "Error linking program:\n%s\n", log));
 158
 159                         free(log);
 160                 }
 161
 162                 glDeleteProgram(basicTexture);
 163
 164                 return 0;
 165         }
 166
 167         glUseProgram(basicTexture);
 168
 169         return 1;
 170 }
 171
 172 void opengl2_shader_cleanup()
 173 {
 174         if (basicTexture) {
 175                 glDeleteProgram(basicTexture);
 176                 basicTexture = 0;
 177         }
 178 }