| // |
| // Book: OpenGL(R) ES 2.0 Programming Guide |
| // Authors: Aaftab Munshi, Dan Ginsburg, Dave Shreiner |
| // ISBN-10: 0321502795 |
| // ISBN-13: 9780321502797 |
| // Publisher: Addison-Wesley Professional |
| // URLs: http://safari.informit.com/9780321563835 |
| // http://www.opengles-book.com |
| // |
| |
| // Simple_TextureCubemap.c |
| // |
| // This is a simple example that draws a sphere with a cubemap image applied. |
| // |
| #include <stdlib.h> |
| #include "esUtil.h" |
| |
| typedef struct |
| { |
| // Handle to a program object |
| GLuint programObject; |
| |
| // Attribute locations |
| GLint positionLoc; |
| GLint normalLoc; |
| |
| // Sampler location |
| GLint samplerLoc; |
| |
| // Texture handle |
| GLuint textureId; |
| |
| // Vertex data |
| int numIndices; |
| GLfloat *vertices; |
| GLfloat *normals; |
| GLushort *indices; |
| |
| } UserData; |
| |
| /// |
| // Create a simple cubemap with a 1x1 face with a different |
| // color for each face |
| GLuint CreateSimpleTextureCubemap( ) |
| { |
| GLuint textureId; |
| // Six 1x1 RGB faces |
| GLubyte cubePixels[6][3] = |
| { |
| // Face 0 - Red |
| 255, 0, 0, |
| // Face 1 - Green, |
| 0, 255, 0, |
| // Face 3 - Blue |
| 0, 0, 255, |
| // Face 4 - Yellow |
| 255, 255, 0, |
| // Face 5 - Purple |
| 255, 0, 255, |
| // Face 6 - White |
| 255, 255, 255 |
| }; |
| |
| // Generate a texture object |
| glGenTextures ( 1, &textureId ); |
| |
| // Bind the texture object |
| glBindTexture ( GL_TEXTURE_CUBE_MAP, textureId ); |
| |
| // Load the cube face - Positive X |
| glTexImage2D ( GL_TEXTURE_CUBE_MAP_POSITIVE_X, 0, GL_RGB, 1, 1, 0, |
| GL_RGB, GL_UNSIGNED_BYTE, &cubePixels[0] ); |
| |
| // Load the cube face - Negative X |
| glTexImage2D ( GL_TEXTURE_CUBE_MAP_NEGATIVE_X, 0, GL_RGB, 1, 1, 0, |
| GL_RGB, GL_UNSIGNED_BYTE, &cubePixels[1] ); |
| |
| // Load the cube face - Positive Y |
| glTexImage2D ( GL_TEXTURE_CUBE_MAP_POSITIVE_Y, 0, GL_RGB, 1, 1, 0, |
| GL_RGB, GL_UNSIGNED_BYTE, &cubePixels[2] ); |
| |
| // Load the cube face - Negative Y |
| glTexImage2D ( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, 0, GL_RGB, 1, 1, 0, |
| GL_RGB, GL_UNSIGNED_BYTE, &cubePixels[3] ); |
| |
| // Load the cube face - Positive Z |
| glTexImage2D ( GL_TEXTURE_CUBE_MAP_POSITIVE_Z, 0, GL_RGB, 1, 1, 0, |
| GL_RGB, GL_UNSIGNED_BYTE, &cubePixels[4] ); |
| |
| // Load the cube face - Negative Z |
| glTexImage2D ( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, GL_RGB, 1, 1, 0, |
| GL_RGB, GL_UNSIGNED_BYTE, &cubePixels[5] ); |
| |
| // Set the filtering mode |
| glTexParameteri ( GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST ); |
| glTexParameteri ( GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_NEAREST ); |
| |
| return textureId; |
| |
| } |
| |
| |
| /// |
| // Initialize the shader and program object |
| // |
| int Init ( ESContext *esContext ) |
| { |
| UserData *userData = esContext->userData; |
| GLbyte vShaderStr[] = |
| "attribute vec4 a_position; \n" |
| "attribute vec3 a_normal; \n" |
| "varying vec3 v_normal; \n" |
| "void main() \n" |
| "{ \n" |
| " gl_Position = a_position; \n" |
| " v_normal = a_normal; \n" |
| "} \n"; |
| |
| GLbyte fShaderStr[] = |
| "precision mediump float; \n" |
| "varying vec3 v_normal; \n" |
| "uniform samplerCube s_texture; \n" |
| "void main() \n" |
| "{ \n" |
| " gl_FragColor = textureCube( s_texture, v_normal );\n" |
| "} \n"; |
| |
| // Load the shaders and get a linked program object |
| userData->programObject = esLoadProgram ( vShaderStr, fShaderStr ); |
| |
| // Get the attribute locations |
| userData->positionLoc = glGetAttribLocation ( userData->programObject, "a_position" ); |
| userData->normalLoc = glGetAttribLocation ( userData->programObject, "a_normal" ); |
| |
| // Get the sampler locations |
| userData->samplerLoc = glGetUniformLocation ( userData->programObject, "s_texture" ); |
| |
| // Load the texture |
| userData->textureId = CreateSimpleTextureCubemap (); |
| |
| // Generate the vertex data |
| userData->numIndices = esGenSphere ( 20, 0.75f, &userData->vertices, &userData->normals, |
| NULL, &userData->indices ); |
| |
| |
| glClearColor ( 0.0f, 0.0f, 0.0f, 0.0f ); |
| return TRUE; |
| } |
| |
| /// |
| // Draw a triangle using the shader pair created in Init() |
| // |
| void Draw ( ESContext *esContext ) |
| { |
| UserData *userData = esContext->userData; |
| |
| // Set the viewport |
| glViewport ( 0, 0, esContext->width, esContext->height ); |
| |
| // Clear the color buffer |
| glClear ( GL_COLOR_BUFFER_BIT ); |
| |
| |
| glCullFace ( GL_BACK ); |
| glEnable ( GL_CULL_FACE ); |
| |
| // Use the program object |
| glUseProgram ( userData->programObject ); |
| |
| // Load the vertex position |
| glVertexAttribPointer ( userData->positionLoc, 3, GL_FLOAT, |
| GL_FALSE, 0, userData->vertices ); |
| // Load the normal |
| glVertexAttribPointer ( userData->normalLoc, 3, GL_FLOAT, |
| GL_FALSE, 0, userData->normals ); |
| |
| glEnableVertexAttribArray ( userData->positionLoc ); |
| glEnableVertexAttribArray ( userData->normalLoc ); |
| |
| // Bind the texture |
| glActiveTexture ( GL_TEXTURE0 ); |
| glBindTexture ( GL_TEXTURE_CUBE_MAP, userData->textureId ); |
| |
| // Set the sampler texture unit to 0 |
| glUniform1i ( userData->samplerLoc, 0 ); |
| |
| glDrawElements ( GL_TRIANGLES, userData->numIndices, |
| GL_UNSIGNED_SHORT, userData->indices ); |
| |
| eglSwapBuffers ( esContext->eglDisplay, esContext->eglSurface ); |
| } |
| |
| /// |
| // Cleanup |
| // |
| void ShutDown ( ESContext *esContext ) |
| { |
| UserData *userData = esContext->userData; |
| |
| // Delete texture object |
| glDeleteTextures ( 1, &userData->textureId ); |
| |
| // Delete program object |
| glDeleteProgram ( userData->programObject ); |
| |
| free ( userData->vertices ); |
| free ( userData->normals ); |
| } |
| |
| |
| int main ( int argc, char *argv[] ) |
| { |
| ESContext esContext; |
| UserData userData; |
| |
| esInitContext ( &esContext ); |
| esContext.userData = &userData; |
| |
| esCreateWindow ( &esContext, TEXT("Simple Texture Cubemap"), 320, 240, ES_WINDOW_RGB ); |
| |
| if ( !Init ( &esContext ) ) |
| return 0; |
| |
| esRegisterDrawFunc ( &esContext, Draw ); |
| |
| esMainLoop ( &esContext ); |
| |
| ShutDown ( &esContext ); |
| } |