FBO 渲染到纹理

  这是书中第八章的最后一节内容,在我机制的简化问题后,写出了想要的效果.应用FBO渲染到纹理,可以直接用.这个用来实现镜面效果什么的,好啊.再一个,貌似我现在已经可以去写延迟渲染流水线了,那个用到多渲染目标,之后再处理.呼,继续学习吧,这些东西还真得实践才行啊.

//RenderToTexture.cpp -- 2013/10/11-20:49#include "stdafx.h"#include <iostream>#include <GLTools.h>#include <GLShaderManager.h>#define FREEGLUT_STATIC#include <GL/glut.h>GLBatchtriangleBatch;GLBatch texturedTriangleBatch ;GLShaderManagershaderManager;GLint triangleShader ;GLint texturedTriangleShader ;GLuint fboName ;GLuint generatedTexutre ;GLenum windowBuffer[] = {GL_BACK_LEFT,} ;GLenum fboBuffers[] = {GL_COLOR_ATTACHMENT0,} ;GLsizei const generatedTextureWidth = 400 ;GLsizei const generatedTextureHeight = 300 ;GLint screenWidth = 800 ;GLint screenHeight = 600 ;void ShutdownRC(void){glDeleteProgram(triangleShader) ;glDeleteProgram(texturedTriangleShader) ;glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0) ;glBindFramebuffer(GL_READ_FRAMEBUFFER, 0) ;glActiveTexture(GL_TEXTURE0) ;glBindTexture(GL_TEXTURE_2D, 0) ;glDeleteTextures(1, &generatedTexutre) ;glDeleteFramebuffers(1, &fboName) ;}void ChangeSize(int w, int h){glViewport(0, 0, w, h);screenWidth = w ;screenHeight = h ;}void SetupRC(){shaderManager.InitializeStockShaders();triangleShader = shaderManager.LoadShaderPairWithAttributes("triangle.vp", "triangle.fp",1,GLT_ATTRIBUTE_VERTEX, "vVertex") ;texturedTriangleShader = shaderManager.LoadShaderPairWithAttributes("texturedTriangle.vp", "texturedTriangle.fp",2,GLT_ATTRIBUTE_VERTEX, "vVertex",GLT_ATTRIBUTE_TEXTURE0, "vTexCoords") ;GLfloat vVerts[] = {-0.5f, 0.0f, 0.0f, 0.5f, 0.0f, 0.0f,0.0f, 0.5f, 0.0f };GLfloat vTexCoords[] = {0, 0,1.0f, 0,0.5f, 1.0f,} ;triangleBatch.Begin(GL_TRIANGLES, 3);triangleBatch.CopyVertexData3f(vVerts);triangleBatch.End();texturedTriangleBatch.Begin(GL_TRIANGLES, 3, 1) ;texturedTriangleBatch.CopyVertexData3f(vVerts) ;texturedTriangleBatch.CopyTexCoordData2f(vTexCoords, 0) ;texturedTriangleBatch.End();glGenFramebuffers(1, &fboName) ;glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fboName) ;glGenTextures(1, &generatedTexutre) ;glBindTexture(GL_TEXTURE_2D, generatedTexutre) ;glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);glGenerateMipmap(GL_TEXTURE_2D);glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, generatedTextureWidth, generatedTextureHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);glBindTexture(GL_TEXTURE_2D, 0);glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, generatedTexutre, 0) ;glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0) ;}void RenderScene(void){//先以黑底画红色三角形到纹理中glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glClearColor(0, 0, 0, 1.0f);glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fboName) ;glDrawBuffers(1, fboBuffers) ;glViewport(0, 0, generatedTextureWidth, generatedTextureHeight) ;glUseProgram(triangleShader) ;GLint iColorLocation = glGetUniformLocation(triangleShader, "vColor") ;GLfloat vColor[] = { 1.0f, 0.0f, 0.0f, 1.0f };glUniform4fv(iColorLocation, 1, vColor) ;triangleBatch.Draw();//再以白底将刚生成的纹理贴到三角形上画出来,汉字好难组织说啊...glClearColor(1.0f, 1.0f, 1.0f, 1.0f);glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0) ;glDrawBuffers(1, windowBuffer) ;glViewport(0, 0, screenWidth, screenHeight) ;glUseProgram(texturedTriangleShader) ;glBindTexture(GL_TEXTURE_2D, generatedTexutre) ;GLint iTextureUniform = glGetUniformLocation(texturedTriangleShader, "colorMap") ;glUniform1i(iTextureUniform, 0) ;texturedTriangleBatch.Draw() ;glutSwapBuffers();}int main(int argc, char* argv[]){gltSetWorkingDirectory(argv[0]);glutInit(&argc, argv);glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);glutInitWindowSize(screenWidth, screenHeight);glutCreateWindow("Render To Texture");glutReshapeFunc(ChangeSize);glutDisplayFunc(RenderScene);GLenum err = glewInit();if (err != GLEW_OK) {fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));return 1;}SetupRC();glutMainLoop();return 0;}