framebuffer對象，麻煩渲染並將紋理傳遞給着色器

我試圖渲染一個簡單的場景到framebuffer，然後將其作爲紋理傳遞給我的着色器。但是，我的渲染對象顯示爲黑色。我無法弄清楚我做錯了什麼。framebuffer對象，麻煩渲染並將紋理傳遞給着色器

在下面的代碼中，我創建了一個FBO併爲其添加了深度緩衝區和紋理。

GLuint fbo, fboDepth,fboTexture; 

// Create the texture 
glGenTexturesEXT(1, &fboTexture); 
glBindTextureEXT(GL_TEXTURE_2D, fboTexture); 
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 512, 512, 0, GL_RGBA, GL_FLOAT, NULL); 
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); 
glTexParameteri(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_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR); 
// Create and bind an FBO 
glGenFramebuffersEXT(1, &fbo); 
glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, fbo); 

// Create depth renderbuffer 
glGenRenderbuffersEXT(1, &fboDepth); 
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fboDepth); 
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, 512, 512); 

glFramebufferTexture2D(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, fboTexture, 0); 
glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, fboDepth); 

GLenum fboStatus = glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER_EXT);         

if (fboStatus != GL_FRAMEBUFFER_COMPLETE) { 
    std::cout << "Couldn't create frame buffer" << std::endl;        
    exit(0);                     
} else { 
    cout << fbo << fboTexture << fboDepth << endl; 
} 

glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0); // Reset framebuffer binding

下面的代碼是我的渲染方法。我用tga紋理嘗試過，效果很好。

void Renderer::render(Geometry* geo) { 
glUseProgram(geo->shader->program); 

// Bind our frame buffer for rendering 
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo); 
glPushAttrib(GL_VIEWPORT_BIT | GL_ENABLE_BIT); 
glViewport(0, 0, 512, 512); 
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    // render a triangle to the fbo 
glBegin(GL_TRIANGLES); 
glColor3f(1,0,0); 
glVertex2f(-1,0); 

glColor3f(0,1,0); 
glVertex2f(1,-1); 

glColor3f(0,0,1); 
glVertex2f(.5,.5); 
glEnd(); 

glPopAttrib(); 
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); 

GLuint texUniLoc = glGetUniformLocation(geo->shader->program, "Tex"); 

glActiveTexture(GL_TEXTURE0 + 1); 
glBindTextureEXT(GL_TEXTURE_2D, fboTexture); 
glUniform1i(texUniLoc, 1); 

GLuint vpm = glGetUniformLocation(geo->shader->program, "ViewProjectionMatrix"); 
glUniformMatrix4fv(vpm, 1, GL_TRUE, ViewProjectionMatrix.vec); 

float * m = (float*)malloc(sizeof(float)*16); 
m[0] = 1; m[1] = 0; m[2] = 0; m[3] = 0; 
m[4] = 0; m[5] = 1; m[6] = 0; m[7] = 0.0; 
m[8] = 0; m[9] = 0; m[10] = 1; m[11] = 0.0; 
m[12] = 0; m[13] = 0; m[14] = 0; m[15] = 1.0; 

    GLuint model = glGetUniformLocation(geo->shader->program, "ModelMatrix"); 
glUniformMatrix4fv(model, 1, GL_TRUE, m); 

// activate and specify pointer to vertex array 
glEnableClientState(GL_VERTEX_ARRAY); 
glEnableClientState(GL_INDEX_ARRAY); 
glEnableClientState(GL_TEXTURE_COORD_ARRAY); 

glVertexPointer(3, GL_FLOAT, 0, geo->vertices); 
glTexCoordPointer(2, GL_FLOAT, 0, geo->texcoords); 
glDrawElements(GL_TRIANGLES, 2*3*32*32, GL_UNSIGNED_SHORT, geo->indices); 

glDisableClientState(GL_VERTEX_ARRAY); 
glDisableClientState(GL_INDEX_ARRAY); 
glDisableClientState(GL_TEXTURE_COORD_ARRAY); 
glUseProgram(0); 
}

我試過.tga紋理和着色器效果很好。我正在使用glfw和glew。此外，我不確定glSomeFunction和glSomeFunctionEXT之間的區別

來源

2012-03-12 nyvaken

我不確定你爲什麼在這裏使用malloc。這是分配內存的絕對*可怕的方式，並且在將它傳遞給glUniform後並不會刪除分配的內存，因此您將在此處發生泄漏。爲什麼不只浮動m [16]？ – Robinson 2012-03-12 22:10:41

你是對的，這是非常臨時的。 – nyvaken 2012-03-13 18:49:07

我修正了它。繪製三角形之前，我不應該調用glUseProgram。

來源

2012-03-13 18:51:54 nyvaken

framebuffer對象，麻煩渲染並將紋理傳遞給着色器

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