openGL着色器学习（一）

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顶点着色器

Identity.vp

// The Identity Shader// Vertex Shader// Richard S. Wright Jr.// OpenGL SuperBible#version 130in vec4 vVertex;void main(void)     {     gl_Position = vVertex;    }

Identity.fp

// The Identity Shader// Fragment Shader// Richard S. Wright Jr.// OpenGL SuperBible#version 130out vec4 vFragColor;uniform vec4 vColor;void main(void)   {    vFragColor = vColor;   }

主程序：

// Triangle.cpp// Our first OpenGL program that will just draw a triangle on the screen.#include <GLTools.h>            // OpenGL toolkit#include <GLShaderManager.h>    // Shader Manager Class#ifdef __APPLE__#include <glut/glut.h>          // OS X version of GLUT#else#define FREEGLUT_STATIC#include <GL/glut.h>            // Windows FreeGlut equivalent#endifGLBatchtriangleBatch;GLShaderManagershaderManager;GLintmyIdentityShader;///////////////////////////////////////////////////////////////////////////////// Window has changed size, or has just been created. In either case, we need// to use the window dimensions to set the viewport and the projection matrix.void ChangeSize(int w, int h)    {glViewport(0, 0, w, h);    }///////////////////////////////////////////////////////////////////////////////// This function does any needed initialization on the rendering context. // This is the first opportunity to do any OpenGL related tasks.void SetupRC(){// Blue backgroundglClearColor(0.0f, 0.0f, 1.0f, 1.0f );    shaderManager.InitializeStockShaders();// Load up a triangleGLfloat vVerts[] = { -0.5f, 0.0f, 0.0f,                   0.5f, 0.0f, 0.0f,  0.0f, 0.5f, 0.0f };triangleBatch.Begin(GL_TRIANGLES, 3);triangleBatch.CopyVertexData3f(vVerts);triangleBatch.End();myIdentityShader = shaderManager.LoadShaderPairWithAttributes("Identity.vp", "Identity.fp", 1, GLT_ATTRIBUTE_VERTEX, "vVertex");}///////////////////////////////////////////////////////////////////////////////// Cleanupvoid ShutdownRC()   {   glDeleteProgram(myIdentityShader);   }///////////////////////////////////////////////////////////////////////////////// Called to draw scenevoid RenderScene(void){// Clear the window with current clearing colorglClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);GLfloat vRed[] = { 1.0f, 0.0f, 0.0f, 1.0f };glUseProgram(myIdentityShader);GLint iColorLocation = glGetUniformLocation(myIdentityShader, "vColor");GLfloat vColor[4] = { 1.0f, 0.0f, 0.0f, 1.0f };glUniform4fv(iColorLocation, 1, vColor);triangleBatch.Draw();// Perform the buffer swap to display back bufferglutSwapBuffers();}///////////////////////////////////////////////////////////////////////////////// Main entry point for GLUT based programsint main(int argc, char* argv[]){gltSetWorkingDirectory(argv[0]);glutInit(&argc, argv);glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STENCIL);glutInitWindowSize(800, 600);glutCreateWindow("Triangle");    glutReshapeFunc(ChangeSize);    glutDisplayFunc(RenderScene);GLenum err = glewInit();if (GLEW_OK != err) {fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));return 1;}SetupRC();glutMainLoop();ShutdownRC();return 0;}

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