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| 1 // | |
| 2 // Book: OpenGL(R) ES 2.0 Programming Guide | |
| 3 // Authors: Aaftab Munshi, Dan Ginsburg, Dave Shreiner | |
| 4 // ISBN-10: 0321502795 | |
| 5 // ISBN-13: 9780321502797 | |
| 6 // Publisher: Addison-Wesley Professional | |
| 7 // URLs: http://safari.informit.com/9780321563835 | |
| 8 // http://www.opengles-book.com | |
| 9 // | |
| 10 | |
| 11 // TextureWrap.c | |
| 12 // | |
| 13 // This is an example that demonstrates the three texture | |
| 14 // wrap modes available on 2D textures | |
| 15 // | |
| 16 #include <stdlib.h> | |
| 17 #include "esUtil.h" | |
| 18 | |
| 19 typedef struct | |
| 20 { | |
| 21 // Handle to a program object | |
| 22 GLuint programObject; | |
| 23 | |
| 24 // Attribute locations | |
| 25 GLint positionLoc; | |
| 26 GLint texCoordLoc; | |
| 27 | |
| 28 // Sampler location | |
| 29 GLint samplerLoc; | |
| 30 | |
| 31 // Offset location | |
| 32 GLint offsetLoc; | |
| 33 | |
| 34 // Texture handle | |
| 35 GLuint textureId; | |
| 36 | |
| 37 } UserData; | |
| 38 | |
| 39 /// | |
| 40 // Generate an RGB8 checkerboard image | |
| 41 // | |
| 42 GLubyte* GenCheckImage( int width, int height, int checkSize ) | |
| 43 { | |
| 44 int x, | |
| 45 y; | |
| 46 GLubyte *pixels = malloc( width * height * 3 ); | |
| 47 | |
| 48 if ( pixels == NULL ) | |
| 49 return NULL; | |
| 50 | |
| 51 for ( y = 0; y < height; y++ ) | |
| 52 for ( x = 0; x < width; x++ ) | |
| 53 { | |
| 54 GLubyte rColor = 0; | |
| 55 GLubyte bColor = 0; | |
| 56 | |
| 57 if ( ( x / checkSize ) % 2 == 0 ) | |
| 58 { | |
| 59 rColor = 255 * ( ( y / checkSize ) % 2 ); | |
| 60 bColor = 255 * ( 1 - ( ( y / checkSize ) % 2 ) ); | |
| 61 } | |
| 62 else | |
| 63 { | |
| 64 bColor = 255 * ( ( y / checkSize ) % 2 ); | |
| 65 rColor = 255 * ( 1 - ( ( y / checkSize ) % 2 ) ); | |
| 66 } | |
| 67 | |
| 68 pixels[(y * height + x) * 3] = rColor; | |
| 69 pixels[(y * height + x) * 3 + 1] = 0; | |
| 70 pixels[(y * height + x) * 3 + 2] = bColor; | |
| 71 } | |
| 72 | |
| 73 return pixels; | |
| 74 } | |
| 75 | |
| 76 /// | |
| 77 // Create a mipmapped 2D texture image | |
| 78 // | |
| 79 GLuint CreateTexture2D( ) | |
| 80 { | |
| 81 // Texture object handle | |
| 82 GLuint textureId; | |
| 83 int width = 256, | |
| 84 height = 256; | |
| 85 GLubyte *pixels; | |
| 86 | |
| 87 pixels = GenCheckImage( width, height, 64 ); | |
| 88 if ( pixels == NULL ) | |
| 89 return 0; | |
| 90 | |
| 91 // Generate a texture object | |
| 92 glGenTextures ( 1, &textureId ); | |
| 93 | |
| 94 // Bind the texture object | |
| 95 glBindTexture ( GL_TEXTURE_2D, textureId ); | |
| 96 | |
| 97 // Load mipmap level 0 | |
| 98 glTexImage2D ( GL_TEXTURE_2D, 0, GL_RGB, width, height, | |
| 99 0, GL_RGB, GL_UNSIGNED_BYTE, pixels ); | |
| 100 | |
| 101 // Set the filtering mode | |
| 102 glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR ); | |
| 103 glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR ); | |
| 104 | |
| 105 return textureId; | |
| 106 | |
| 107 } | |
| 108 | |
| 109 | |
| 110 /// | |
| 111 // Initialize the shader and program object | |
| 112 // | |
| 113 int Init ( ESContext *esContext ) | |
| 114 { | |
| 115 UserData *userData = esContext->userData; | |
| 116 GLbyte vShaderStr[] = | |
| 117 "uniform float u_offset; \n" | |
| 118 "attribute vec4 a_position; \n" | |
| 119 "attribute vec2 a_texCoord; \n" | |
| 120 "varying vec2 v_texCoord; \n" | |
| 121 "void main() \n" | |
| 122 "{ \n" | |
| 123 " gl_Position = a_position; \n" | |
| 124 " gl_Position.x += u_offset;\n" | |
| 125 " v_texCoord = a_texCoord; \n" | |
| 126 "} \n"; | |
| 127 | |
| 128 GLbyte fShaderStr[] = | |
| 129 "precision mediump float; \n" | |
| 130 "varying vec2 v_texCoord; \n" | |
| 131 "uniform sampler2D s_texture; \n" | |
| 132 "void main() \n" | |
| 133 "{ \n" | |
| 134 " gl_FragColor = texture2D( s_texture, v_texCoord );\n" | |
| 135 "} \n"; | |
| 136 | |
| 137 // Load the shaders and get a linked program object | |
| 138 userData->programObject = esLoadProgram ( vShaderStr, fShaderStr ); | |
| 139 | |
| 140 // Get the attribute locations | |
| 141 userData->positionLoc = glGetAttribLocation ( userData->programObject, "a_pos
ition" ); | |
| 142 userData->texCoordLoc = glGetAttribLocation ( userData->programObject, "a_tex
Coord" ); | |
| 143 | |
| 144 // Get the sampler location | |
| 145 userData->samplerLoc = glGetUniformLocation ( userData->programObject, "s_tex
ture" ); | |
| 146 | |
| 147 // Get the offset location | |
| 148 userData->offsetLoc = glGetUniformLocation( userData->programObject, "u_offse
t" ); | |
| 149 | |
| 150 // Load the texture | |
| 151 userData->textureId = CreateTexture2D (); | |
| 152 | |
| 153 glClearColor ( 0.0f, 0.0f, 0.0f, 0.0f ); | |
| 154 return TRUE; | |
| 155 } | |
| 156 | |
| 157 /// | |
| 158 // Draw a triangle using the shader pair created in Init() | |
| 159 // | |
| 160 void Draw ( ESContext *esContext ) | |
| 161 { | |
| 162 UserData *userData = esContext->userData; | |
| 163 GLfloat vVertices[] = { -0.3f, 0.3f, 0.0f, 1.0f, // Position 0 | |
| 164 -1.0f, -1.0f, // TexCoord 0 | |
| 165 -0.3f, -0.3f, 0.0f, 1.0f, // Position 1 | |
| 166 -1.0f, 2.0f, // TexCoord 1 | |
| 167 0.3f, -0.3f, 0.0f, 1.0f, // Position 2 | |
| 168 2.0f, 2.0f, // TexCoord 2 | |
| 169 0.3f, 0.3f, 0.0f, 1.0f, // Position 3 | |
| 170 2.0f, -1.0f // TexCoord 3 | |
| 171 }; | |
| 172 GLushort indices[] = { 0, 1, 2, 0, 2, 3 }; | |
| 173 | |
| 174 // Set the viewport | |
| 175 glViewport ( 0, 0, esContext->width, esContext->height ); | |
| 176 | |
| 177 // Clear the color buffer | |
| 178 glClear ( GL_COLOR_BUFFER_BIT ); | |
| 179 | |
| 180 // Use the program object | |
| 181 glUseProgram ( userData->programObject ); | |
| 182 | |
| 183 // Load the vertex position | |
| 184 glVertexAttribPointer ( userData->positionLoc, 4, GL_FLOAT, | |
| 185 GL_FALSE, 6 * sizeof(GLfloat), vVertices ); | |
| 186 // Load the texture coordinate | |
| 187 glVertexAttribPointer ( userData->texCoordLoc, 2, GL_FLOAT, | |
| 188 GL_FALSE, 6 * sizeof(GLfloat), &vVertices[4] ); | |
| 189 | |
| 190 glEnableVertexAttribArray ( userData->positionLoc ); | |
| 191 glEnableVertexAttribArray ( userData->texCoordLoc ); | |
| 192 | |
| 193 // Bind the texture | |
| 194 glActiveTexture ( GL_TEXTURE0 ); | |
| 195 glBindTexture ( GL_TEXTURE_2D, userData->textureId ); | |
| 196 | |
| 197 // Set the sampler texture unit to 0 | |
| 198 glUniform1i ( userData->samplerLoc, 0 ); | |
| 199 | |
| 200 // Draw quad with repeat wrap mode | |
| 201 glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT ); | |
| 202 glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT ); | |
| 203 glUniform1f ( userData->offsetLoc, -0.7f ); | |
| 204 glDrawElements ( GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices ); | |
| 205 | |
| 206 // Draw quad with clamp to edge wrap mode | |
| 207 glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE ); | |
| 208 glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE ); | |
| 209 glUniform1f ( userData->offsetLoc, 0.0f ); | |
| 210 glDrawElements ( GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices ); | |
| 211 | |
| 212 // Draw quad with mirrored repeat | |
| 213 glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT ); | |
| 214 glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT ); | |
| 215 glUniform1f ( userData->offsetLoc, 0.7f ); | |
| 216 glDrawElements ( GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices ); | |
| 217 | |
| 218 eglSwapBuffers ( esContext->eglDisplay, esContext->eglSurface ); | |
| 219 } | |
| 220 | |
| 221 /// | |
| 222 // Cleanup | |
| 223 // | |
| 224 void ShutDown ( ESContext *esContext ) | |
| 225 { | |
| 226 UserData *userData = esContext->userData; | |
| 227 | |
| 228 // Delete texture object | |
| 229 glDeleteTextures ( 1, &userData->textureId ); | |
| 230 | |
| 231 // Delete program object | |
| 232 glDeleteProgram ( userData->programObject ); | |
| 233 } | |
| 234 | |
| 235 | |
| 236 int main ( int argc, char *argv[] ) | |
| 237 { | |
| 238 ESContext esContext; | |
| 239 UserData userData; | |
| 240 | |
| 241 esInitContext ( &esContext ); | |
| 242 esContext.userData = &userData; | |
| 243 | |
| 244 esCreateWindow ( &esContext, "MipMap 2D", 640, 480, ES_WINDOW_RGB ); | |
| 245 | |
| 246 if ( !Init ( &esContext ) ) | |
| 247 return 0; | |
| 248 | |
| 249 esRegisterDrawFunc ( &esContext, Draw ); | |
| 250 | |
| 251 esMainLoop ( &esContext ); | |
| 252 | |
| 253 ShutDown ( &esContext ); | |
| 254 } | |
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Chromium Code Reviews
Issue 543002:
Renamed gles_book_examples to gles2_book to make it shorter and more correct.... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/