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Diffstat (limited to 'samples/gles2_book/Simple_TextureCubemap/Simple_TextureCubemap.c')
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1 files changed, 229 insertions, 0 deletions
diff --git a/samples/gles2_book/Simple_TextureCubemap/Simple_TextureCubemap.c b/samples/gles2_book/Simple_TextureCubemap/Simple_TextureCubemap.c new file mode 100644 index 00000000..302d844f --- /dev/null +++ b/samples/gles2_book/Simple_TextureCubemap/Simple_TextureCubemap.c @@ -0,0 +1,229 @@ +// +// 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 ); +} |