Demo涵盖了OpenGL ES 3.0 的一系列新特性：
1、VAO和VBO
2、帧缓冲对象
3、MRT
效果：
代码：
//yf's version
#define STB_IMAGE_IMPLEMENTATION
#include <stdlib.h>
#include "esUtil.h"
#include "stb_image.h" typedef struct
{
// Handle to a program object
GLuint programObject;
GLuint programObjectQuad; GLuint cubeVAO, cubeVBO;
GLuint floorVAO, floorVBO;
GLuint quadVAO, quadVBO;
GLuint framebuffer; ESMatrix mvMatrix;
ESMatrix mvpMatrix; GLuint mvLoc;
GLuint mvpLoc; GLuint cubeTexture;
GLuint floorTexture; // Rotation angle
GLfloat angle; GLuint texIDfloor;
GLuint texIDcube; GLuint texColorbuffer;
GLuint texColorArray[]; GLuint textureWidth;
GLuint textureHeight;
} UserData; GLfloat cubeVertices[] = {
// Positions // Texture Coords
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, -0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f, -0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f
};
GLfloat floorVertices[] = {
// Positions // Texture Coords (note we set these higher than 1 that together with GL_REPEAT as texture wrapping mode will cause the floor texture to repeat)
5.0f, -0.5f, 5.0f, 2.0f, 0.0f,
-5.0f, -0.5f, 5.0f, 0.0f, 0.0f,
-5.0f, -0.5f, -5.0f, 0.0f, 2.0f, 5.0f, -0.5f, 5.0f, 2.0f, 0.0f,
-5.0f, -0.5f, -5.0f, 0.0f, 2.0f,
5.0f, -0.5f, -5.0f, 2.0f, 2.0f
};
//渲染到这个四边形
GLfloat quadVertices[] = { // Vertex attributes for a quad that fills the entire screen in Normalized Device Coordinates.
// Positions // TexCoords
-1.0f, 1.0f, 0.0f, 1.0f,
-1.0f, -1.0f, 0.0f, 0.0f,
1.0f, -1.0f, 1.0f, 0.0f, -1.0f, 1.0f, 0.0f, 1.0f,
1.0f, -1.0f, 1.0f, 0.0f,
1.0f, 1.0f, 1.0f, 1.0f
}; GLuint screenWidth = ;
GLuint screenHeight = ; GLuint LoadTextureFile(const char* filename)
{
GLuint texID;
glGenTextures(, &texID);
glBindTexture(GL_TEXTURE_2D, texID);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
int width, height, nrChannels;
unsigned char *data = stbi_load(filename, &width, &height, &nrChannels, );
if (data)
{
glTexImage2D(GL_TEXTURE_2D, , GL_RGB, width, height, , GL_RGB, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
}
else
printf("Failed to load texture\n");
stbi_image_free(data);
return texID;
} char vShaderStr[] =
"#version 300 es \n"
"layout(location = 0) in vec4 a_position; \n"
"layout(location = 1) in vec2 a_texCoord; \n"
"uniform mat4 u_mvpMatrix; \n"
"out vec2 v_texCoord; \n"
"void main() \n"
"{ \n"
" gl_Position = u_mvpMatrix * a_position; \n"
" v_texCoord=a_texCoord; \n"
"} \n"; char fShaderStr[] =
"#version 300 es \n"
"precision mediump float; \n"
"in vec2 v_texCoord; \n"
"uniform sampler2D screenTexture; \n"
"out vec4 outColor; \n"
"void main() \n"
"{ \n"
" outColor = texture(screenTexture,v_texCoord); \n"
"} \n"; //填充quad面片的VS
char vScreenShaderStr[] =
"#version 300 es \n"
"layout(location = 0) in vec2 a_position; \n"
"layout(location = 1) in vec2 texCoord; \n"
"out vec2 v_texCoord; \n"
"void main() \n"
"{ \n"
" gl_Position = vec4(a_position.x,a_position.y,0.0,1.0); \n"
" v_texCoord=texCoord; \n"
"} \n"; ////正常：outColor=texture(Texture,v_texCoord);
char fScreenShaderStr[] = //正常Shader
"#version 300 es \n"
"precision mediump float; \n"
"out vec4 outColor; \n"
"in vec2 v_texCoord; \n"
"uniform sampler2D Texture; \n"
"void main() \n"
"{ \n"
//" outColor=texture(Texture,v_texCoord); \n"//正常色
" outColor=vec4(vec3(1.0-texture(Texture,v_texCoord)),1.0); \n"//反色
"} \n"; char fScreenShaderStrKernel[] =//核效果着色器
"#version 300 es \n"
"precision mediump float; \n"
"const float offset=1.0/300.0; \n"
"layout(location = 0) out vec4 outColor0; \n"
"layout(location = 1) out vec4 outColor1; \n"
"layout(location = 2) out vec4 outColor2; \n"
"layout(location = 3) out vec4 outColor3; \n"
"in vec2 v_texCoord; \n"
"uniform sampler2D Texture; \n"
"void main() \n"
"{ \n"
" vec2 offsets[9] = vec2[]( \n"
" vec2(-offset, offset), \n"
" vec2(0.0f, offset), \n"
" vec2(offset, offset), \n"
" vec2(-offset, 0.0f), \n"
" vec2(0.0f, 0.0f), \n"
" vec2(offset, 0.0f), \n"
" vec2(-offset, -offset), \n"
" vec2(0.0f, -offset), \n"
" vec2(offset, -offset) \n"
" ); \n" " float kernel[9] = float[]( \n"//模糊核0
" 1.0/16.0, 2.0/16.0, 1.0/16.0, \n"
" 2.0/16.0, 4.0/16.0, 2.0/16.0, \n"
" 1.0/16.0, 2.0/16.0, 1.0/16.0 \n"
" ); \n"
" vec3 sampleTex[9]; \n"
" for (int i = 0; i < 9; i++) \n"
" { \n"
" sampleTex[i] = vec3(texture(Texture, v_texCoord.st + offsets[i])); \n"
" } \n"
" vec3 col = vec3(0.0); \n"
" for (int i = 0; i < 9; i++) \n"
" col += sampleTex[i] * kernel[i]; \n"
" outColor0 = vec4(col, 1.0); \n" " kernel = float[]( \n"//锐化核1
" -1, -1, -1, \n"
" -1, 9, -1, \n"
" -1, -1, -1 \n"
" ); \n"
" for (int i = 0; i < 9; i++) \n"
" { \n"
" sampleTex[i] = vec3(texture(Texture, v_texCoord.st + offsets[i])); \n"
" } \n"
" col = vec3(0.0); \n"
" for (int i = 0; i < 9; i++) \n"
" col += sampleTex[i] * kernel[i]; \n"
" outColor1 = vec4(col, 1.0); \n"
" outColor2 = texture(Texture,v_texCoord); \n"//正常色2
" outColor3 = vec4(vec3(1.0-texture(Texture,v_texCoord)),1.0); \n"//反色3
"} \n"; int Init(ESContext *esContext)
{
UserData *userData = esContext->userData;
userData->textureWidth = ;
userData->textureHeight = ;
// Load the shaders and get a linked program object
userData->programObject = esLoadProgram(vShaderStr, fShaderStr);//载入文件、附件、编译、判错、删除Shader
userData->programObjectQuad = esLoadProgram(vScreenShaderStr, fScreenShaderStrKernel); userData->angle = 0.0f;
userData->mvLoc = glGetUniformLocation(userData->programObject, "u_mvMatrix");
userData->mvpLoc = glGetUniformLocation(userData->programObject, "u_mvpMatrix");
//cube
glGenVertexArrays(, &userData->cubeVAO);//初始化cube的vao
glGenBuffers(, &userData->cubeVBO);//初始化装载cube属性的vbo
glBindVertexArray(userData->cubeVAO);//以下操作对cubeVAO负责
glBindBuffer(GL_ARRAY_BUFFER, userData->cubeVBO);//以下操作对cubeVBO负责
glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVertices), cubeVertices, GL_STATIC_DRAW);//复制数据到当前vbo
glVertexAttribPointer(, , GL_FLOAT, GL_FALSE, sizeof(GLfloat) * , (GLvoid*));//设置顶点位置
glEnableVertexAttribArray();
glVertexAttribPointer(, , GL_FLOAT, GL_FALSE, sizeof(GLfloat) * , (GLvoid*)(sizeof(GLfloat) * ));
glEnableVertexAttribArray();
userData->texIDcube = LoadTextureFile("container.jpg");
glBindVertexArray();//完成cubeVAO的设置
//floor
glGenVertexArrays(, &userData->floorVAO);//初始化地板vao
glGenBuffers(, &userData->floorVBO);
glBindVertexArray(userData->floorVAO);
glBindBuffer(GL_ARRAY_BUFFER, userData->floorVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(floorVertices), floorVertices, GL_STATIC_DRAW);
glEnableVertexAttribArray();
glVertexAttribPointer(, , GL_FLOAT, GL_FALSE, sizeof(GLfloat) * , (GLvoid*));
glEnableVertexAttribArray();
glVertexAttribPointer(, , GL_FLOAT, GL_FALSE, sizeof(GLfloat) * , (GLvoid*)(sizeof(GLfloat) * ));
userData->texIDfloor = LoadTextureFile("brick_DIFF.bmp");
glBindVertexArray();//完成floorVAO的设置
//quad
glGenVertexArrays(, &userData->quadVAO);
glGenBuffers(, &userData->quadVBO);
glBindVertexArray(userData->quadVAO);
glBindBuffer(GL_ARRAY_BUFFER, userData->quadVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), quadVertices, GL_STATIC_DRAW);
glEnableVertexAttribArray();
glVertexAttribPointer(, , GL_FLOAT, GL_FALSE, sizeof(GLfloat) * , (GLvoid*));
glEnableVertexAttribArray();
glVertexAttribPointer(, , GL_FLOAT, GL_FALSE, sizeof(GLfloat) * , (GLvoid*)(sizeof(GLfloat) * ));
glBindVertexArray(); //GLuint defaultFramebuffer = 0;
const GLenum attachments[] = {
GL_COLOR_ATTACHMENT0,
GL_COLOR_ATTACHMENT1,
GL_COLOR_ATTACHMENT2,
GL_COLOR_ATTACHMENT3
};
//glGetIntegerv(GL_FRAMEBUFFER_BINDING, &defaultFramebuffer); //设置FBO
glGenFramebuffers(, &userData->framebuffer);//初始化帧缓冲framebuffer
glBindFramebuffer(GL_FRAMEBUFFER, userData->framebuffer);//以下代码对framebuffer负责,包括纹理附件设置和rbo附件设置
glGenTextures(, &userData->texColorArray);
for (int i = ; i < ; i++){
//userData->texColorArray[i] = generateAttachmentTexture(GL_FALSE, GL_FALSE);//纹理附件
glBindTexture(GL_TEXTURE_2D, userData->texColorArray[i]);
glTexImage2D(GL_TEXTURE_2D, , GL_RGBA,
userData->textureWidth, userData->textureHeight,
, GL_RGBA, GL_UNSIGNED_BYTE, NULL);//设置宽高但不赋予纹理文件的数据
// Set the filtering mode
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glBindTexture(GL_TEXTURE_2D, );
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, GL_TEXTURE_2D, userData->texColorArray[i], );//完成FBO的纹理附件挂载
}
glDrawBuffers(, attachments);
if (GL_FRAMEBUFFER_COMPLETE != glCheckFramebufferStatus(GL_FRAMEBUFFER))
return FALSE; //设置渲染缓冲对象附件
GLuint rbo;
glGenRenderbuffers(, &rbo);//初始化rbo附件
glBindRenderbuffer(GL_RENDERBUFFER, rbo);//以下操作对rbo负责
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, screenWidth, screenHeight);
glBindRenderbuffer(GL_RENDERBUFFER, );//完成对rbo的设置
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rbo);//完成FBO的rbo附件挂载 if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
printf("ERROR::FRAMEBUFFER:: Framebuffer is not complete!"); glBindFramebuffer(GL_FRAMEBUFFER, );//完成纹理附件和rbo附件的设置，解绑fbo glClearColor(1.0f, 1.0f, 1.0f, 0.0f);//初始刷新一下
glEnable(GL_DEPTH_TEST);
return TRUE;
} void Update(ESContext *esContext, float deltaTime)
{
UserData *userData = esContext->userData; userData->angle += (deltaTime * 50.0f);//转动
if (userData->angle >= 360.0f)
userData->angle -= 360.0f; esMatrixLoadIdentity(&userData->mvMatrix);
esTranslate(&userData->mvMatrix, 0.0f, 0.0f, -3.0f);
esRotate(&userData->mvMatrix, userData->angle, 0.0f, 1.0f, 0.0f); ESMatrix perspective;
esMatrixLoadIdentity(&perspective);//单位化一个矩阵作为透视投影矩阵
float aspect = (GLfloat)esContext->width / ((GLfloat)esContext->height);
esPerspective(&perspective, .f, aspect, 0.2f, .f); esMatrixMultiply(&userData->mvpMatrix, &userData->mvMatrix, &perspective);
} void DrawQuad(ESContext *esContext)
{
UserData *userData = esContext->userData;
glBindFramebuffer(GL_FRAMEBUFFER, userData->framebuffer);
glViewport(, , esContext->width, esContext->height);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
glUseProgram(userData->programObject);//启用programObject
glUniformMatrix4fv(userData->mvpLoc, , GL_FALSE, (GLfloat *)&userData->mvpMatrix);//mvpMatrix在Update里更新 glBindVertexArray(userData->cubeVAO);
glBindTexture(GL_TEXTURE_2D, userData->texIDcube);
glDrawArrays(GL_TRIANGLES, , );
glBindVertexArray(); glBindVertexArray(userData->floorVAO);
glBindTexture(GL_TEXTURE_2D, userData->texIDfloor);
glDrawArrays(GL_TRIANGLES, , );
glBindVertexArray();
glBindFramebuffer(GL_FRAMEBUFFER, ); // Bind to default framebuffer again and draw the quad plane with attched screen texture.
glBindFramebuffer(GL_FRAMEBUFFER, userData->framebuffer);//闪烁是因为重复渲染了三维图像和QUAD
glUseProgram(userData->programObjectQuad);//启用programObjectQuad
glBindVertexArray(userData->quadVAO);
glBindTexture(GL_TEXTURE_2D, userData->texColorArray[]);//texColorArray在Init里绑定到了fbo的纹理Attachment
glDrawArrays(GL_TRIANGLES, , );
glBindVertexArray();
glBindFramebuffer(GL_FRAMEBUFFER, );
//ID号为0表示缺省帧缓存，即默认的window提供的帧缓存。因此，在glBindFramebuffer()中将ID号设置为0可以解绑定当前FBO。
} void BlitTextures(ESContext *esContext)//区位块传送
{
UserData *userData = esContext->userData; // set the fbo for reading
glBindFramebuffer(GL_READ_FRAMEBUFFER, userData->framebuffer);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, );
// Copy the output red buffer to lower left quadrant
glReadBuffer(GL_COLOR_ATTACHMENT0);
glBlitFramebuffer(, , userData->textureWidth, userData->textureHeight,
, , esContext->width / , esContext->height / ,
GL_COLOR_BUFFER_BIT, GL_LINEAR);
//(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
// GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter) // Copy the output green buffer to lower right quadrant
glReadBuffer(GL_COLOR_ATTACHMENT1);
glBlitFramebuffer(, , userData->textureWidth, userData->textureHeight,
esContext->width / , , esContext->width, esContext->height / ,
GL_COLOR_BUFFER_BIT, GL_LINEAR); // Copy the output blue buffer to upper left quadrant
glReadBuffer(GL_COLOR_ATTACHMENT2);
glBlitFramebuffer(, , userData->textureWidth, userData->textureHeight,
, esContext->height / , esContext->width / , esContext->height,
GL_COLOR_BUFFER_BIT, GL_LINEAR); // Copy the output gray buffer to upper right quadrant
glReadBuffer(GL_COLOR_ATTACHMENT3);
glBlitFramebuffer(, , userData->textureWidth, userData->textureHeight,
esContext->width / , esContext->height / , esContext->width, esContext->height,
GL_COLOR_BUFFER_BIT, GL_LINEAR);
} void Draw(ESContext *esContext)
{
DrawQuad(esContext);
BlitTextures(esContext);
} void ShutDown(ESContext *esContext)
{
UserData *userData = esContext->userData; glDeleteVertexArrays(, &userData->cubeVAO);
glDeleteBuffers(, &userData->cubeVBO);
glDeleteVertexArrays(, &userData->floorVAO);
glDeleteBuffers(, &userData->floorVBO);
glDeleteVertexArrays(, &userData->quadVAO);
glDeleteBuffers(, &userData->quadVBO); glDeleteBuffers(, userData->texColorArray);
glDeleteFramebuffers(, &userData->framebuffer); glDeleteProgram(userData->programObject);
glDeleteProgram(userData->programObjectQuad);
} int esMain(ESContext *esContext)
{
esContext->userData = malloc(sizeof(UserData)); esCreateWindow(esContext, "正常，反色，模糊，锐化", screenWidth, screenHeight, ES_WINDOW_RGB | ES_WINDOW_ALPHA | ES_WINDOW_DEPTH); if (!Init(esContext))
{
return GL_FALSE;
}
esRegisterShutdownFunc(esContext, ShutDown);
esRegisterUpdateFunc(esContext, Update);
esRegisterDrawFunc(esContext, Draw); return GL_TRUE;
}