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Diffstat (limited to 'tests/Simple_Texture2D/main.c')
| -rw-r--r-- | tests/Simple_Texture2D/main.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/tests/Simple_Texture2D/main.c b/tests/Simple_Texture2D/main.c new file mode 100644 index 0000000..498bb9e --- /dev/null +++ b/tests/Simple_Texture2D/main.c @@ -0,0 +1,216 @@ +// +// 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_Texture2D.c +// +// This is a simple example that draws a quad with a 2D +// texture image. The purpose of this example is to demonstrate +// the basics of 2D texturing +// +#include <stdlib.h> +#include "esUtil.h" + +GLubyte blue=0; + +typedef struct +{ + // Handle to a program object + GLuint programObject; + + // Attribute locations + GLint positionLoc; + GLint texCoordLoc; + + // Sampler location + GLint samplerLoc; + + // Texture handle + GLuint textureId; + + float time; +} UserData; + +/// +// Create a simple 2x2 texture image with four different colors +// +GLuint CreateSimpleTexture2D( ) +{ + // Texture object handle + GLuint textureId; + + // 2x2 Image, 3 bytes per pixel (R, G, B) + GLubyte pixels[4 * 3] = + { + 255, 0, 0, // Red + 0, 255, 0, // Green + 0, 0, 255, // Blue + 255, 255, 0 // Yellow + }; + + pixels[2] = blue; + if (blue == 255) + blue =0; + blue++; + + // Use tightly packed data + glPixelStorei ( GL_UNPACK_ALIGNMENT, 1 ); + + // Generate a texture object + glGenTextures ( 1, &textureId ); + + // Bind the texture object + glBindTexture ( GL_TEXTURE_2D, textureId ); + + // Load the texture + glTexImage2D ( GL_TEXTURE_2D, 0, GL_RGB, 2, 2, 0, GL_RGB, GL_UNSIGNED_BYTE, pixels ); + + // Set the filtering mode + glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST ); + glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST ); + + return textureId; + +} + + +/// +// Initialize the shader and program object +// +int Init ( ESContext *esContext ) +{ + esContext->userData = malloc(sizeof(UserData)); + UserData *userData = esContext->userData; + GLbyte vShaderStr[] = + "attribute vec4 a_position; \n" + "attribute vec2 a_texCoord; \n" + "varying vec2 v_texCoord; \n" + "void main() \n" + "{ \n" + " gl_Position = a_position; \n" + " v_texCoord = a_texCoord; \n" + "} \n"; + + GLbyte fShaderStr[] = + "precision mediump float; \n" + "varying vec2 v_texCoord; \n" + "uniform sampler2D s_texture; \n" + "void main() \n" + "{ \n" + " gl_FragColor = texture2D( s_texture, v_texCoord );\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->texCoordLoc = glGetAttribLocation ( userData->programObject, "a_texCoord" ); + + // Get the sampler location + userData->samplerLoc = glGetUniformLocation ( userData->programObject, "s_texture" ); + + // Load the texture + userData->textureId = CreateSimpleTexture2D (); + userData->time = 1.0f; + + glClearColor ( 0.0f, 0.0f, 0.0f, 0.0f ); + return GL_TRUE; +} + +void Update(ESContext *esContext, float deltaTime) { + UserData *userData = esContext ->userData; + + glDeleteTextures ( 1, &userData->textureId ); + userData->textureId = CreateSimpleTexture2D (); +} + +/// +// Draw a triangle using the shader pair created in Init() +// +void Draw ( ESContext *esContext ) +{ + UserData *userData = esContext->userData; + GLfloat vVertices[] = { -0.5f, 0.5f, 0.0f, // Position 0 + 0.0f, 0.0f, // TexCoord 0 + -0.5f, -0.5f, 0.0f, // Position 1 + 0.0f, 1.0f, // TexCoord 1 + 0.5f, -0.5f, 0.0f, // Position 2 + 1.0f, 1.0f, // TexCoord 2 + 0.5f, 0.5f, 0.0f, // Position 3 + 1.0f, 0.0f // TexCoord 3 + }; + GLushort indices[] = { 0, 1, 2, 0, 2, 3 }; + + // Set the viewport + glViewport ( 0, 0, esContext->width, esContext->height ); + + // Clear the color buffer + glClear ( GL_COLOR_BUFFER_BIT ); + + // Use the program object + glUseProgram ( userData->programObject ); + + // Load the vertex position + glVertexAttribPointer ( userData->positionLoc, 3, GL_FLOAT, + GL_FALSE, 5 * sizeof(GLfloat), vVertices ); + // Load the texture coordinate + glVertexAttribPointer ( userData->texCoordLoc, 2, GL_FLOAT, + GL_FALSE, 5 * sizeof(GLfloat), &vVertices[3] ); + + glEnableVertexAttribArray ( userData->positionLoc ); + glEnableVertexAttribArray ( userData->texCoordLoc ); + + // Bind the texture + glActiveTexture ( GL_TEXTURE0 ); + glBindTexture ( GL_TEXTURE_2D, userData->textureId ); + + // Set the sampler texture unit to 0 + glUniform1i ( userData->samplerLoc, 0 ); + + glDrawElements ( GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices ); + +} + +/// +// Cleanup +// +void ShutDown ( ESContext *esContext ) +{ + UserData *userData = esContext->userData; + + // Delete texture object + glDeleteTextures ( 1, &userData->textureId ); + + // Delete program object + glDeleteProgram ( userData->programObject ); + + free(esContext->userData); +} + +int main ( int argc, char *argv[] ) +{ + ESContext esContext; + UserData userData; + + esInitContext ( &esContext ); + esContext.userData = &userData; + + esCreateWindow ( &esContext, "Simple Texture 2D", 320, 240, ES_WINDOW_RGB ); + + if ( !Init ( &esContext ) ) + return 0; + + esRegisterDrawFunc ( &esContext, Draw ); + esRegisterUpdateFunc ( &esContext, Update); + + esMainLoop ( &esContext ); + + ShutDown ( &esContext ); +} |