【发布时间】：2014-03-18 09:23:48
【问题描述】：
我在屏幕上绘制了很多点，我试图让它们渲染到纹理以进行后期处理，然后再将纹理渲染回屏幕。目前我正试图通过并获得纹理渲染，但它似乎什么也没渲染。
我的片段着色器工作（没有渲染到纹理 - 在 mEllipseTextureProgram 中使用波纹管），我所做的唯一更改是包含
out vec3 color;
渲染到纹理本身（显然更改为 color= 而不是 gl_FragColor=）。下面引用的第二个程序（mScreenProgram）如下：
顶点着色器：
#version 330 compatibility
in vec2 vUV;
out vec2 UV;
void main()
{
gl_Position = gl_Vertex;
UV = vUV;
}
片段着色器：
#version 330 core
in vec2 UV;
out vec3 color;
uniform sampler2D renderedTexture;
void main(){
color = texture( renderedTexture, UV ).xyz;
}
我将渲染设置为纹理 stuff，如下所示：
glGenFramebuffers(1, &mGaussianFrameBuffer);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mGaussianFrameBuffer);
glGenTextures(1, &mGaussianRenderTexture);
glBindTexture(GL_TEXTURE_2D, mGaussianRenderTexture);
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_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA,
1024,
768,
0, GL_RGBA, GL_UNSIGNED_BYTE,
NULL);
glBindTexture(GL_TEXTURE_2D, 0);
glFramebufferTexture(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, mGaussianRenderTexture, 0);
glGenTextures(1, &mGaussianDepthBuffer);
glBindTexture(GL_TEXTURE_2D, mGaussianDepthBuffer);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
1024,
768,
0, GL_DEPTH_COMPONENT, GL_FLOAT,
NULL);
glBindTexture(GL_TEXTURE_2D, 0);
glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, mGaussianDepthBuffer, 0);
返回一个成功的 GL_FRAMEBUFFER_COMPLETE。
以下是三个相关的渲染函数：
void Draw()
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//gluPerspective(45, 1024.0/768.0, 3.0, 20000);
perspectiveGL(45, 1024.0/768.0, 1.0, 20000);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glPushMatrix();
gluLookAt(cameraData[0],cameraData[1], cameraData[2],
cameraData[3],cameraData[4], cameraData[5],
0,1,0);
glEnable(GL_DEPTH_TEST);
glClearColor( 0.2f, 0.2f, 0.9f, 0.0f );
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// OTHER STUFF POTENTIALLY DRAW HERE IN DIFFERENT WAYS
glUseProgram(mEllipseTextureProgram);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mGaussianFrameBuffer);
GLuint attachments[1] = {GL_COLOR_ATTACHMENT0};
glDrawBuffers(1, attachments);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
DrawEllipseToTexture();
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
glUseProgram(mScreenProgram);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
DrawTextureToScreen();
}
void DrawEllipseToTexture()
{
glEnableClientState(GL_VERTEX_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER, mVBO);
glVertexPointer(3, GL_FLOAT, 0, 0);
glEnable(GL_PROGRAM_POINT_SIZE);
glEnable(GL_POINT_SPRITE);
glEnable( GL_TEXTURE_2D );
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, mBMP);
glProgramUniform1i(mEllipseTextureProgram, mTextureLocation, 0);
glBindBuffer(GL_ARRAY_BUFFER, mUV);
glEnableVertexAttribArray(mTexCoordLocation);
glVertexAttribPointer(mTexCoordLocation, 2, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, mSpacial);
glEnableVertexAttribArray(mSpacialLocation);
glVertexAttribPointer(mSpacialLocation, 1, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, mNormals);
glEnableVertexAttribArray(mNormalLocation);
glVertexAttribPointer(mNormalLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, mVerticalSpat);
glEnableVertexAttribArray(mMajorLocation);
glVertexAttribPointer(mMajorLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, mHorizontalSpat);
glEnableVertexAttribArray(mMinorLocation);
glVertexAttribPointer(mMinorLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable( GL_BLEND );
glDrawArrays(GL_POINTS, 0, mNumberPoints);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glDisable( GL_TEXTURE_2D );
glDisableVertexAttribArray(mSpacialLocation);
glDisable(GL_POINT_SPRITE);
glDisable( GL_POINT_SMOOTH );
glDisable(GL_PROGRAM_POINT_SIZE);
glDisableClientState(GL_VERTEX_ARRAY);
}
void DrawTextureToScreen()
{
glEnableClientState(GL_VERTEX_ARRAY);
glEnable( GL_TEXTURE_2D );
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, mGaussianRenderTexture);
glProgramUniform1i(mScreenProgram, mGaussianTextureLocation, 0);
GLfloat vertices[] = { -1, -1, 2,
1, -1, 2,
1, 1, 2,
-1, 1, 2 };
GLfloat uv[] = { 0, 0,
1, 0,
1, 1,
0, 1,};
glVertexPointer(3, GL_FLOAT, 0, vertices);
glEnableVertexAttribArray(mGaussianUV);
glVertexAttribPointer(mGaussianUV, 2, GL_FLOAT, GL_FALSE, 0, uv);
glDrawArrays(GL_TRIANGLES, 0, 4);
glDisable ( GL_TEXTURE_2D );
glDisableClientState(GL_VERTEX_ARRAY);
}
【问题讨论】：
标签： c++ opengl glsl shader render