[英]OpenGL es 2.0 Gaussian blur on triangle
我最近学习了opengl es 2.0，现在我尝试对自己生成的三角形进行高斯模糊。 我在网络上有一些难以理解的示例，并且大多数将模糊应用于图像。 我知道我必须使用帧缓冲区，但我不知道如何在其上绘制三角形并应用模糊。 是否有可能在 C++ 中看到一个真实完整的代码并有很好的解释？
编辑 ：
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#define GLFW_INCLUDE_ES2
#include <GLFW/glfw3.h>
#include "shaders.hpp"
#include "camera.hpp"
unsigned int vbo, cbo, tbo;
GLuint _fbo, _fbo2, _tex, _tex2;
static const GLuint WIDTH = 800;
static const GLuint HEIGHT = 600;
GLuint pos, col, tex, normal;
camera * _camera = new camera();
static const GLfloat vertices[] = {
0.0f, 1.0f, 0.0f,
1.0f, -1.0f, 0.0f,
-1.0f, -1.0f, 0.0f
};
static const GLfloat colors[] = {
0.0f, 0.5f, 1.0f,
0.5f, 0.5f, 1.0f,
0.5f, 0.5f, 1.0f
};
static const GLfloat texture[] = {
1.0f, 1.0f,
1.0f, 0.0f,
0.0f, 1.0f
};
int main(void){
GLFWwindow* window;
shaders * shaderBasic;
GLuint pId;
glm::mat4 projection; static glm::mat4 view; static glm::mat4 model;
glfwInit();
glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
window = glfwCreateWindow(WIDTH, HEIGHT, __FILE__, NULL, NULL);
glfwMakeContextCurrent(window);
printf("GL_VERSION : %s\n", glGetString(GL_VERSION) );
printf("GL_RENDERER : %s\n", glGetString(GL_RENDERER) );
std::string vs, fs;
vs = "basic.vs";
fs = "basic.fs";
shaderBasic = new shaders(vs, fs);
shaderBasic->CompileShader();
shaderBasic->LinkShader();
pId = shaderBasic->getProgramId();
pos = glGetAttribLocation(pId, "position");
col = glGetAttribLocation(pId, "colors");
tex = glGetAttribLocation(pId, "tex");
fs = "lastBlur.fs";
shaders * blurShader;
GLuint pIdBlur;
blurShader = new shaders(vs, fs);
blurShader->CompileShader();
blurShader->LinkShader();
pIdBlur = blurShader->getProgramId();
_camera->setPositionCamera(glm::vec3(0, 0, -1));
_camera->setLookAtCamera(glm::vec3(0, 0, 0));
_camera->setFieldOfView(45);
_camera->setAspect(WIDTH, HEIGHT);
_camera->setViewport(WIDTH, HEIGHT);
_camera->getMatricies(projection, view, model);
glGenFramebuffers(1, &_fbo);
glGenTextures(1, &_tex);
glBindFramebuffer(GL_FRAMEBUFFER, _fbo);
glBindTexture(GL_TEXTURE_2D, _tex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, WIDTH/2, HEIGHT/2, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, _tex, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
std::cout << "ERROR::FRAMEBUFFER:: Framebuffer is not complete!" << std::endl;
else{
std::cout << "FRAMEBUFFER COMPLETE" << std::endl;
}
auto sampTex = glGetUniformLocation(pIdBlur, "texture0");
std::cerr << "sampTex : " << sampTex << std::endl;
glUniform1i(sampTex, 0);
while (!glfwWindowShouldClose(window)) {
// glViewport(0, 0, WIDTH, HEIGHT);
glBindFramebuffer(GL_FRAMEBUFFER, _fbo);
glClearColor(0.0f, 0.0f, 0.4f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// glViewport(0, 0, WIDTH/2, HEIGHT/2);
glUseProgram(pIdBlur);
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(pos, 3, GL_FLOAT, false, 0, 0);
glEnableVertexAttribArray(pos);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glGenBuffers(1, &cbo);
glBindBuffer(GL_ARRAY_BUFFER, cbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW);
glVertexAttribPointer(col, 2, GL_FLOAT, false, 0, 0);
glEnableVertexAttribArray(col);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glGenBuffers(1, &tbo);
glBindBuffer(GL_ARRAY_BUFFER, tbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(texture), texture, GL_STATIC_DRAW);
glVertexAttribPointer(tex, 2, GL_FLOAT, false, 0, 0);
glEnableVertexAttribArray(tex);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(pId);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, _tex);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwPollEvents();
glfwSwapBuffers(window);
}
glDeleteBuffers(1, &vbo);
glfwTerminate();
return EXIT_SUCCESS;
}
模糊着色器：
#version 100
precision mediump float;
uniform sampler2D texture0;
varying vec3 vColor;
varying vec2 TexCoords;
vec4 blur13(sampler2D image, vec2 uv, vec2 resolution, vec2 direction) {
vec4 color = vec4(0.0);
vec2 off1 = vec2(1.411764705882353) * direction;
vec2 off2 = vec2(3.2941176470588234) * direction;
vec2 off3 = vec2(5.176470588235294) * direction;
color += texture2D(image, uv) * 0.1964825501511404;
color += texture2D(image, uv + (off1 / resolution)) * 0.2969069646728344;
color += texture2D(image, uv - (off1 / resolution)) * 0.2969069646728344;
color += texture2D(image, uv + (off2 / resolution)) * 0.09447039785044732;
color += texture2D(image, uv - (off2 / resolution)) * 0.09447039785044732;
color += texture2D(image, uv + (off3 / resolution)) * 0.010381362401148057;
color += texture2D(image, uv - (off3 / resolution)) * 0.010381362401148057;
return color;
}
void main(){
gl_FragColor = blur13(texture0, TexCoords, vec2(400, 300), vec2(1.0, 0.0));
}
我假设您已经交换了pIdBlur和pId 。
我将向您介绍具有 2 个通道的高斯模糊着色器。 这是一个近似值，它首先在第一遍中沿 X 轴模糊，在第二遍中沿 Y 轴模糊。 这导致更好的强模糊性能。 模糊着色器使用正态（或高斯）分布。 对于 2 个通道，使用相同的着色器程序，2 个通道的单独方向设置存储在统一的vec2 u_dir 。 模糊效果的强度可以在 [0.0, 1.0] 范围内随统一变量float u_sigma变化。
模糊顶点着色器
precision mediump float;
attribute vec2 inPos;
varying vec2 pos;
void main()
{
pos = inPos;
gl_Position = vec4( inPos, 0.0, 1.0 );
}
模糊片段着色器
precision mediump float;
varying vec2 pos;
uniform sampler2D u_texture;
uniform vec2 u_textureSize;
uniform float u_sigma;
uniform vec2 u_dir;
float CalcGauss( float x, float sigma )
{
if ( sigma <= 0.0 )
return 0.0;
return exp( -(x*x) / (2.0 * sigma) ) / (2.0 * 3.14157 * sigma);
}
void main()
{
vec2 texC = pos.st * 0.5 + 0.5;
vec4 texCol = texture2D( u_texture, texC );
vec4 gaussCol = vec4( texCol.rgb, 1.0 );
vec2 step = u_dir / u_textureSize;
for ( int i = 1; i <= 32; ++ i )
{
float weight = CalcGauss( float(i) / 32.0, u_sigma * 0.5 );
if ( weight < 1.0/255.0 )
break;
texCol = texture2D( u_texture, texC + step * float(i) );
gaussCol += vec4( texCol.rgb * weight, weight );
texCol = texture2D( u_texture, texC - step * float(i) );
gaussCol += vec4( texCol.rgb * weight, weight );
}
gaussCol.rgb = clamp( gaussCol.rgb / gaussCol.w, 0.0, 1.0 );
gl_FragColor = vec4( gaussCol.rgb, 1.0 );
}
程序链接后，可以从以下位置读取统一位置和属性索引：
GLint attrInxPos = glGetAttribLocation( pIdBlur, "inPos" );
GLint locTexture = glGetUniformLocation( pIdBlur, "u_texture" );
GLint locTexSize = glGetUniformLocation( pIdBlur, "u_textureSize" );
GLint locSigma = glGetUniformLocation( pIdBlur, "u_sigma" );
GLint locDir = glGetUniformLocation( pIdBlur, "u_dir" );
必须创建一个顶点数组对象，其中包含一个四边形，稍后将在整个视口上绘制，用于屏幕空间模糊传递：
GLuint screenVAO;
glGenVertexArrays( 1, &screenVAO );
glBindVertexArray( screenVAO );
GLuint quadBuf;
glGenBuffers( 1, &quadBuf );
glBindBuffer( GL_ARRAY_BUFFER, quadBuf );
GLfloat screenRect[] = { -1.0f, -1.0f, 1.0f, -1.0f, -1.0f, 1.0f, 1.0f, 1.0f };
glBufferData( GL_ARRAY_BUFFER, 8 * sizeof( float ), screenRect, GL_STATIC_DRAW );
glEnableVertexAttribArray( attrInxPos );
glVertexAttribPointer( attrInxPos, 2, GL_FLOAT, GL_FALSE, 0, nullptr );
必须创建 2 个帧缓冲区，纹理附加到其颜色平面。 在第一个场景中绘制。 第二个用于第一个模糊通道。 第二个模糊通道直接绘制到绘图缓冲区。
GLuint texObj[2];
GLuint fbObj[2];
glGenTextures(2, texObj);
glGenFramebuffers(2, fbObj);
glActiveTexture(GL_TEXTURE0);
for ( int i = 0; i < 2; i ++ )
{
glBindTexture(GL_TEXTURE_2D, texObj[i]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glBindFramebuffer(GL_FRAMEBUFFER, fbObj[i]);
glFramebufferTexture2D( GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texObj[i], 0 );
GLuint renderbuffer;
glGenRenderbuffers(1, &renderbuffer);
glBindRenderbuffer( GL_RENDERBUFFER, renderbuffer );
glRenderbufferStorage( GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, width, height );
glFramebufferRenderbuffer( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, renderbuffer );
}
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
现在已经生成了模糊通道所需的一切。
要绘制和模糊场景，必须应用以下步骤。 首先，您必须绑定并清除第一个帧缓冲区
glBindFramebuffer(GL_FRAMEBUFFER, fbObj[0]);
glClearColor(0.0f, 0.0f, 0.4f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
并使用着色器程序绘制对象：
glUseProgram(pId);
现在绘制场景的对象。
.....
glDrawArrays(GL_TRIANGLES, 0, 3);
第二步是第一个模糊通道。 必须使用模糊程序并且必须绑定第二个帧缓冲区。 释放第 1 帧缓冲区后，您可以使用附加到其颜色平面的纹理作为模糊着色器的输入。
请注意，纹理不能同时是源和目标，这会导致未定义的行为。
要将纹理绑定到着色器，您必须将纹理绑定到纹理单元，并将纹理单元的索引分配给着色器的均匀采样器。
int texUnitIndex = 1;
GLfloat texSize = { width, height };
GLfloat dirX[] = { 1.0f, 0.0f };
GLfloat sigma = .....; // 0.0 <= sigma <= 1.0
glBindFramebuffer(GL_FRAMEBUFFER, fbObj[1]);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(pIdBlur);
glActiveTexture(GL_TEXTURE0 + texUnitIndex);
glBindTexture(GL_TEXTURE_2D, texObj[0]);
glUniform1i(locTexture, texUnitIndex);
glUniform2fv(locTexSize, texSize);
glUniform2fv(locTexSize, dirX);
glUniform1f(locTexSize, sigma);
要应用模糊通道，必须在视口区域中绘制四边形。
glBindVertexArray( screenVAO );
glDrawArrays( GL_TRIANGLE_STRIP, 0, 4 );
第二个也是最后一个模糊通道，类似于第一个模糊通道。 第一个模糊通道的目标纹理是源纹理，目标是绘图缓冲区。 必须为视口的 Y 轴设置模糊方向。
GLfloat dirY[] = { 0.0f, 1.0f };
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBindTexture(GL_TEXTURE_2D, texObj[1]);
glUniform2fv(locTexSize, dirY);
另请参阅以下问题的答案：
另请参阅类似的 WebGL 示例：
(function loadscene() { var resize, gl, progDraw, progBlur, vp_size, blurFB; var canvas, camera, bufCube = {}, bufQuad = {}; var shininess = 10.0, glow = 10.0, sigma = 0.8, radius = 1.0; function render(deltaMS){ var sliderScale = 100; sigma = document.getElementById( "sigma" ).value / sliderScale; radius = document.getElementById( "radius" ).value / sliderScale; vp_size = [canvas.width, canvas.height]; camera.Update( vp_size ); gl.enable( gl.DEPTH_TEST ); gl.clearColor( 0.0, 0.0, 0.0, 1.0 ); gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT ); // set up framebuffer gl.bindFramebuffer( gl.FRAMEBUFFER, blurFB[0] ); gl.viewport( 0, 0, blurFB[0].width, blurFB[0].height ); gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT ); // setup view projection and model var prjMat = camera.Perspective(); var viewMat = camera.LookAt(); var modelMat = RotateAxis( IdentM44(), Fract( deltaMS / 13000.0 ) * 2.0 * Math.PI, 0 ); modelMat = RotateAxis( modelMat, Fract( deltaMS / 17000.0 ) * 2.0 * Math.PI, 1 ); // set up draw shader ShProg.Use( progDraw ); ShProg.SetM44( progDraw, "u_projectionMat44", prjMat ); ShProg.SetM44( progDraw, "u_modelViewMat44", Multiply(viewMat, modelMat) ); ShProg.SetF1( progDraw, "u_shininess", shininess ); // draw scene VertexBuffer.Draw( bufCube ); // set blur-X framebuffer and bind frambuffer texture gl.bindFramebuffer( gl.FRAMEBUFFER, blurFB[1] ); gl.viewport( 0, 0, blurFB[1].width, blurFB[1].height ); gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT ); var texUnit = 1; gl.activeTexture( gl.TEXTURE0 + texUnit ); gl.bindTexture( gl.TEXTURE_2D, blurFB[0].color0_texture ); // set up blur-X shader ShProg.Use( progBlur ); ShProg.SetI1( progBlur, "u_texture", texUnit ) ShProg.SetF2( progBlur, "u_textureSize", vp_size ); ShProg.SetF1( progBlur, "u_sigma", sigma ) ShProg.SetF1( progBlur, "u_radius", radius ) ShProg.SetF2( progBlur, "u_dir", [1.0, 0.0] ) // draw full screen space gl.enableVertexAttribArray( progBlur.inPos ); gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos ); gl.vertexAttribPointer( progBlur.inPos, 2, gl.FLOAT, false, 0, 0 ); gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx ); gl.drawElements( gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0 ); gl.disableVertexAttribArray( progBlur.inPos ); // reset framebuffer and bind frambuffer texture gl.bindFramebuffer( gl.FRAMEBUFFER, null ); gl.viewport( 0, 0, vp_size[0], vp_size[1] ); gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT ); texUnit = 2; gl.activeTexture( gl.TEXTURE0 + texUnit ); gl.bindTexture( gl.TEXTURE_2D, blurFB[1].color0_texture ); // set up pst process shader ShProg.SetI1( progBlur, "u_texture", texUnit ) ShProg.SetF1( progBlur, "u_radius", radius ) ShProg.SetF2( progBlur, "u_dir", [0.0, 1.0] ) // draw full screen space gl.enableVertexAttribArray( progBlur.inPos ); gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos ); gl.vertexAttribPointer( progBlur.inPos, 2, gl.FLOAT, false, 0, 0 ); gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx ); gl.drawElements( gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0 ); gl.disableVertexAttribArray( progBlur.inPos ); requestAnimationFrame(render); } function initScene() { canvas = document.getElementById( "canvas"); gl = canvas.getContext( "experimental-webgl" ); if ( !gl ) return null; progDraw = ShProg.Create( [ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER }, { source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER } ] ); if ( !progDraw.progObj ) return null; progDraw.inPos = gl.getAttribLocation( progDraw.progObj, "inPos" ); progDraw.inNV = gl.getAttribLocation( progDraw.progObj, "inNV" ); progDraw.inCol = gl.getAttribLocation( progDraw.progObj, "inCol" ); progBlur = ShProg.Create( [ { source : "post-shader-vs", stage : gl.VERTEX_SHADER }, { source : "blur-shader-fs", stage : gl.FRAGMENT_SHADER } ] ); progBlur.inPos = gl.getAttribLocation( progBlur.progObj, "inPos" ); if ( !progBlur.progObj ) return; // create cube var cubePos = [ -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0 ]; var cubeCol = [ 1.0, 0.0, 0.0, 1.0, 0.5, 0.0, 1.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0 ]; var cubeHlpInx = [ 0, 1, 2, 3, 1, 5, 6, 2, 5, 4, 7, 6, 4, 0, 3, 7, 3, 2, 6, 7, 1, 0, 4, 5 ]; var cubePosData = []; for ( var i = 0; i < cubeHlpInx.length; ++ i ) { cubePosData.push( cubePos[cubeHlpInx[i]*3], cubePos[cubeHlpInx[i]*3+1], cubePos[cubeHlpInx[i]*3+2] ); } var cubeNVData = []; for ( var i1 = 0; i1 < cubeHlpInx.length; i1 += 4 ) { var nv = [0, 0, 0]; for ( i2 = 0; i2 < 4; ++ i2 ) { var i = i1 + i2; nv[0] += cubePosData[i*3]; nv[1] += cubePosData[i*3+1]; nv[2] += cubePosData[i*3+2]; } for ( i2 = 0; i2 < 4; ++ i2 ) cubeNVData.push( nv[0], nv[1], nv[2] ); } var cubeColData = []; for ( var is = 0; is < 6; ++ is ) { for ( var ip = 0; ip < 4; ++ ip ) { cubeColData.push( cubeCol[is*3], cubeCol[is*3+1], cubeCol[is*3+2] ); } } var cubeInxData = []; for ( var i = 0; i < cubeHlpInx.length; i += 4 ) { cubeInxData.push( i, i+1, i+2, i, i+2, i+3 ); } bufCube = VertexBuffer.Create( [ { data : cubePosData, attrSize : 3, attrLoc : progDraw.inPos }, { data : cubeNVData, attrSize : 3, attrLoc : progDraw.inNV }, { data : cubeColData, attrSize : 3, attrLoc : progDraw.inCol } ], cubeInxData ); bufQuad.pos = gl.createBuffer(); gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos ); gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( [ -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0 ] ), gl.STATIC_DRAW ); bufQuad.inx = gl.createBuffer(); gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx ); gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( [ 0, 1, 2, 0, 2, 3 ] ), gl.STATIC_DRAW ); camera = new Camera( [0, 3, 0.0], [0, 0, 0], [0, 0, 1], 90, vp_size, 0.5, 100 ); window.onresize = resize; resize(); requestAnimationFrame(render); } function resize() { //vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight]; vp_size = [window.innerWidth, window.innerHeight] //vp_size = [256, 256] canvas.width = vp_size[0]; canvas.height = vp_size[1]; var fbsize = Math.max(vp_size[0], vp_size[1]); fbsize = 1 << 31 - Math.clz32(fbsize); // nearest power of 2 blurFB = []; for ( var i = 0; i < 2; ++ i ) { fb = gl.createFramebuffer(); fb.width = fbsize; fb.height = fbsize; gl.bindFramebuffer( gl.FRAMEBUFFER, fb ); fb.color0_texture = gl.createTexture(); gl.bindTexture( gl.TEXTURE_2D, fb.color0_texture ); gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST ); gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST ); gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, fb.width, fb.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null ); fb.renderbuffer = gl.createRenderbuffer(); gl.bindRenderbuffer( gl.RENDERBUFFER, fb.renderbuffer ); gl.renderbufferStorage( gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, fb.width, fb.height ); gl.framebufferTexture2D( gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, fb.color0_texture, 0 ); gl.framebufferRenderbuffer( gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, fb.renderbuffer ); gl.bindTexture( gl.TEXTURE_2D, null ); gl.bindRenderbuffer( gl.RENDERBUFFER, null ); gl.bindFramebuffer( gl.FRAMEBUFFER, null ); blurFB.push( fb ); } } function Fract( val ) { return val - Math.trunc( val ); } function CalcAng( deltaTime, intervall ) { return Fract( deltaTime / (1000*intervall) ) * 2.0 * Math.PI; } function CalcMove( deltaTime, intervall, range ) { var pos = self.Fract( deltaTime / (1000*intervall) ) * 2.0 var pos = pos < 1.0 ? pos : (2.0-pos) return range[0] + (range[1] - range[0]) * pos; } function EllipticalPosition( a, b, angRag ) { var a_b = a * a - b * b var ea = (a_b <= 0) ? 0 : Math.sqrt( a_b ); var eb = (a_b >= 0) ? 0 : Math.sqrt( -a_b ); return [ a * Math.sin( angRag ) - ea, b * Math.cos( angRag ) - eb, 0 ]; } function IdentM44() { return [ 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1 ]; }; function RotateAxis(matA, angRad, axis) { var aMap = [ [1, 2], [2, 0], [0, 1] ]; var a0 = aMap[axis][0], a1 = aMap[axis][1]; var sinAng = Math.sin(angRad), cosAng = Math.cos(angRad); var matB = matA.slice(0); for ( var i = 0; i < 3; ++ i ) { matB[a0*4+i] = matA[a0*4+i] * cosAng + matA[a1*4+i] * sinAng; matB[a1*4+i] = matA[a0*4+i] * -sinAng + matA[a1*4+i] * cosAng; } return matB; } function Rotate(matA, angRad, axis) { var s = Math.sin(angRad), c = Math.cos(angRad); var x = axis[0], y = axis[1], z = axis[2]; matB = [ x*x*(1-c)+c, x*y*(1-c)-z*s, x*z*(1-c)+y*s, 0, y*x*(1-c)+z*s, y*y*(1-c)+c, y*z*(1-c)-x*s, 0, z*x*(1-c)-y*s, z*y*(1-c)+x*s, z*z*(1-c)+c, 0, 0, 0, 0, 1 ]; return Multiply(matA, matB); } function Multiply(matA, matB) { matC = IdentM44(); for (var i0=0; i0<4; ++i0 ) for (var i1=0; i1<4; ++i1 ) matC[i0*4+i1] = matB[i0*4+0] * matA[0*4+i1] + matB[i0*4+1] * matA[1*4+i1] + matB[i0*4+2] * matA[2*4+i1] + matB[i0*4+3] * matA[3*4+i1] return matC; } function Cross( a, b ) { return [ a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 ]; } function Dot( a, b ) { return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; } function Normalize( v ) { var len = Math.sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] ); return [ v[0] / len, v[1] / len, v[2] / len ]; } Camera = function( pos, target, up, fov_y, vp, near, far ) { this.Time = function() { return Date.now(); } this.pos = pos; this.target = target; this.up = up; this.fov_y = fov_y; this.vp = vp; this.near = near; this.far = far; this.Perspective = function() { var n = this.near; var f = this.far; var fn = f + n; var f_n = f - n; var r = this.vp[0] / this.vp[1]; var t = 1 / Math.tan( Math.PI * this.fov_y / 360 ); return [ t/r, 0, 0, 0, 0, t, 0, 0, 0, 0, -fn/f_n, -1, 0, 0, -2*f*n/f_n, 0 ]; }; this.LookAt = function() { var mz = Normalize( [ this.pos[0]-this.target[0], this.pos[1]-this.target[1], this.pos[2]-this.target[2] ] ); var mx = Normalize( Cross( this.up, mz ) ); var my = Normalize( Cross( mz, mx ) ); var tx = Dot( mx, this.pos ); var ty = Dot( my, this.pos ); var tz = Dot( [-mz[0], -mz[1], -mz[2]], this.pos ); return [mx[0], my[0], mz[0], 0, mx[1], my[1], mz[1], 0, mx[2], my[2], mz[2], 0, tx, ty, tz, 1]; }; this.Update = function(vp_size) { if (vp_size) this.vp = vp_size; }; } var ShProg = { Create: function (shaderList) { var shaderObjs = []; for (var i_sh = 0; i_sh < shaderList.length; ++i_sh) { var shderObj = this.Compile(shaderList[i_sh].source, shaderList[i_sh].stage); if (shderObj) shaderObjs.push(shderObj); } var prog = {} prog.progObj = this.Link(shaderObjs) if (prog.progObj) { prog.attrInx = {}; var noOfAttributes = gl.getProgramParameter(prog.progObj, gl.ACTIVE_ATTRIBUTES); for (var i_n = 0; i_n < noOfAttributes; ++i_n) { var name = gl.getActiveAttrib(prog.progObj, i_n).name; prog.attrInx[name] = gl.getAttribLocation(prog.progObj, name); } prog.uniLoc = {}; var noOfUniforms = gl.getProgramParameter(prog.progObj, gl.ACTIVE_UNIFORMS); for (var i_n = 0; i_n < noOfUniforms; ++i_n) { var name = gl.getActiveUniform(prog.progObj, i_n).name; prog.uniLoc[name] = gl.getUniformLocation(prog.progObj, name); } } return prog; }, AttrI: function (prog, name) { return prog.attrInx[name]; }, UniformL: function (prog, name) { return prog.uniLoc[name]; }, Use: function (prog) { gl.useProgram(prog.progObj); }, SetI1: function (prog, name, val) { if (prog.uniLoc[name]) gl.uniform1i(prog.uniLoc[name], val); }, SetF1: function (prog, name, val) { if (prog.uniLoc[name]) gl.uniform1f(prog.uniLoc[name], val); }, SetF2: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform2fv(prog.uniLoc[name], arr); }, SetF3: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform3fv(prog.uniLoc[name], arr); }, SetF4: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform4fv(prog.uniLoc[name], arr); }, SetM33: function (prog, name, mat) { if (prog.uniLoc[name]) gl.uniformMatrix3fv(prog.uniLoc[name], false, mat); }, SetM44: function (prog, name, mat) { if (prog.uniLoc[name]) gl.uniformMatrix4fv(prog.uniLoc[name], false, mat); }, Compile: function (source, shaderStage) { var shaderScript = document.getElementById(source); if (shaderScript) source = shaderScript.text; var shaderObj = gl.createShader(shaderStage); gl.shaderSource(shaderObj, source); gl.compileShader(shaderObj); var status = gl.getShaderParameter(shaderObj, gl.COMPILE_STATUS); if (!status) alert(gl.getShaderInfoLog(shaderObj)); return status ? shaderObj : null; }, Link: function (shaderObjs) { var prog = gl.createProgram(); for (var i_sh = 0; i_sh < shaderObjs.length; ++i_sh) gl.attachShader(prog, shaderObjs[i_sh]); gl.linkProgram(prog); status = gl.getProgramParameter(prog, gl.LINK_STATUS); if ( !status ) alert(gl.getProgramInfoLog(prog)); return status ? prog : null; } }; var VertexBuffer = { Create: function(attribs, indices, type) { var buffer = { buf: [], attr: [], inx: gl.createBuffer(), inxLen: indices.length, primitive_type: type ? type : gl.TRIANGLES }; for (var i=0; i<attribs.length; ++i) { buffer.buf.push(gl.createBuffer()); buffer.attr.push({ size : attribs[i].attrSize, loc : attribs[i].attrLoc, no_of: attribs[i].data.length/attribs[i].attrSize }); gl.bindBuffer(gl.ARRAY_BUFFER, buffer.buf[i]); gl.bufferData(gl.ARRAY_BUFFER, new Float32Array( attribs[i].data ), gl.STATIC_DRAW); } gl.bindBuffer(gl.ARRAY_BUFFER, null); if ( buffer.inxLen > 0 ) { gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffer.inx); gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( indices ), gl.STATIC_DRAW); gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null); } return buffer; }, Draw: function(bufObj) { for (var i=0; i<bufObj.buf.length; ++i) { gl.bindBuffer(gl.ARRAY_BUFFER, bufObj.buf[i]); gl.vertexAttribPointer(bufObj.attr[i].loc, bufObj.attr[i].size, gl.FLOAT, false, 0, 0); gl.enableVertexAttribArray( bufObj.attr[i].loc); } if ( bufObj.inxLen > 0 ) { gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, bufObj.inx); gl.drawElements(bufObj.primitive_type, bufObj.inxLen, gl.UNSIGNED_SHORT, 0); gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null ); } else gl.drawArrays(bufObj.primitive_type, 0, bufObj.attr[0].no_of ); for (var i=0; i<bufObj.buf.length; ++i) gl.disableVertexAttribArray(bufObj.attr[i].loc); gl.bindBuffer( gl.ARRAY_BUFFER, null ); } }; initScene(); })();
html,body { margin: 0; overflow: hidden; } #gui { position : absolute; top : 0; left : 0; }
<script id="draw-shader-vs" type="x-shader/x-vertex"> precision mediump float; attribute vec3 inPos; attribute vec3 inNV; attribute vec3 inCol; varying vec3 vertPos; varying vec3 vertNV; varying vec3 vertCol; uniform mat4 u_projectionMat44; uniform mat4 u_modelViewMat44; void main() { vertNV = mat3( u_modelViewMat44 ) * normalize( inNV ); vertCol = inCol; vec4 pos = u_modelViewMat44 * vec4( inPos, 1.0 ); vertPos = pos.xyz / pos.w; gl_Position = u_projectionMat44 * pos; } </script> <script id="draw-shader-fs" type="x-shader/x-fragment"> precision mediump float; varying vec3 vertPos; varying vec3 vertNV; varying vec3 vertCol; uniform float u_shininess; void main() { vec3 color = vertCol; vec3 normalV = normalize( vertNV ); vec3 eyeV = normalize( -vertPos ); vec3 halfV = normalize( eyeV + normalV ); float NdotH = max( 0.0, dot( normalV, halfV ) ); float shineFac = ( u_shininess + 2.0 ) * pow( NdotH, u_shininess ) / ( 2.0 * 3.14159265 ); gl_FragColor = vec4( color.rgb * (0.2 + NdotH), 1.0 ); } </script> <script id="post-shader-vs" type="x-shader/x-vertex"> precision mediump float; attribute vec2 inPos; varying vec2 pos; void main() { pos = inPos; gl_Position = vec4( inPos, 0.0, 1.0 ); } </script> <script id="blur-shader-fs" type="x-shader/x-fragment"> precision mediump float; varying vec2 pos; uniform sampler2D u_texture; uniform vec2 u_textureSize; uniform float u_sigma; uniform float u_radius; uniform vec2 u_dir; float CalcGauss( float x, float sigma ) { if ( sigma <= 0.0 ) return 0.0; return exp( -(x*x) / (2.0 * sigma) ) / (2.0 * 3.14157 * sigma); } void main() { vec2 texC = pos.st * 0.5 + 0.5; vec4 texCol = texture2D( u_texture, texC ); vec4 gaussCol = vec4( texCol.rgb, 1.0 ); vec2 step = u_dir / u_textureSize; for ( int i = 1; i <= 32; ++ i ) { float weight = CalcGauss( float(i) / 32.0, u_sigma * 0.5 ); if ( weight < 1.0/255.0 ) break; texCol = texture2D( u_texture, texC + u_radius * step * float(i) ); gaussCol += vec4( texCol.rgb * weight, weight ); texCol = texture2D( u_texture, texC - u_radius * step * float(i) ); gaussCol += vec4( texCol.rgb * weight, weight ); } gaussCol.rgb = clamp( gaussCol.rgb / gaussCol.w, 0.0, 1.0 ); gl_FragColor = vec4( gaussCol.rgb, 1.0 ); } </script> <div> <form id="gui" name="inputs"> <table> <tr> <td> <font color= #CCF>radius</font> </td> <td> <input type="range" id="radius" min="1" max="1000" value="200"/></td> </tr> <tr> <td> <font color= #CCF>blur</font> </td> <td> <input type="range" id="sigma" min="1" max="50" value="10"/></td> </tr> </table> </form> </div> <canvas id="canvas" style="border: none;"></canvas>
通常，您需要将要模糊的场景绘制到带有附加纹理的帧缓冲对象 (FBO)。
此时，绘图的其余部分应该与您的主缓冲区完全相同，但请确保您设置了正确的视口。 此过程将使您绘制纹理。
现在您的场景有了纹理，您需要执行与模糊图像相同的过程。
然后，您可以使用具有 2 个调用的水平和垂直模糊着色器对其进行优化，这些调用使用另一个 FBO ...
所以我会尝试在您的应用程序中执行一些步骤：
如果您发现自己在任何这些方面遇到麻烦，您可能想提出一个具体的问题。
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带有OpenGL ES 2.0的SDL2-无法在iOS上绘制简单的三角形
[英]SDL2 With OpenGL ES 2.0 - Cannot draw simple triangle on iOS
OpenGL：OpenGL-ES之外的Triangle Strip中的退化三角形是可以接受的吗？
[英]OpenGL: Are degenerate triangles in a Triangle Strip acceptable outside of OpenGL-ES?
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