C ++ Opengl Glsl着色器性能问题

Question

So recently I have been programming an fps game on my laptop but when I tried to run the game on my stationary computer which should perform better it runs slower??

Here is a couple of screenshots comparing a simple test scene with and without skybox. ( Stationary computer - Top, Laptop - Bottom)

As you can see so far this is what I would excpect, but when I add the same skybox rendering code + shader code ( Stationary computer - Top, Laptop - Bottom)

As you can see now the results are the complete opposite and I have no clue why infact if I look up or back with skybox on my stationary computer I get an fps of about 5.

Here is the shader code for the skybox:

#version 120
varying vec3 pl;
uniform mat4 gWM;
void main()
{
    pl = vec3(gl_Vertex);
    gl_Position = (gWM * gl_Vertex).xyww; // I have also tried with gl_ModelViewProjectionMatrix instead of gWM.
}

Fragment shader:

#version 120
varying vec3 pl;
uniform samplerCube cubeMap;
void main()
{
    gl_FragData[1] = textureCube(cubeMap, -pl);
}

The actual mesh rendered is a sphere.

And another thing is that my laptop can also handle my lighting calculations with 100+ fps left, but if I add those to my stationary then I get about 15.

If my stationary would perform worse in the beginning I wouldn't care about why but since it doesn't I really want to know where the fps is lost!

stationary computer specs:

CPU: Intel Core i5 @ 2.80GHz

RAM: 4,00GB Dual-Channel

Graphics: ATI Radeon HD 4800 Series

laptop specs:

CPU: Intel Core i7 @2.00GHz

RAM: 8,00GB Dual-Channel

Graphics: Intel HD Graphics 4000

Rendering (Updated) For rendering I use a G-Buffer that is setup like this ( from a tutorial in deffered lighting ):

        glGenFramebuffers(1, &m_fbo);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_fbo);

glGenTextures(ARRAY_ELEMENTS(m_textures), m_textures);
glGenRenderbuffers(1, &m_depthBuffer);
glGenTextures(1, &m_finalTexture);

for(unsigned int i = 0; i < ARRAY_ELEMENTS(m_textures); i++){
    glBindTexture(GL_TEXTURE_2D, m_textures[i]);
    glTexImage2D(GL_TEXTURE_2D, 0, i == 0 ? GL_RGBA32F : GL_RGB8, WindowWidth, WindowHeight, 0, GL_RGB, GL_FLOAT, NULL);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, GL_TEXTURE_2D, m_textures[i], 0);
}

glBindRenderbuffer(GL_RENDERBUFFER, m_depthBuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8_EXT, WindowWidth, WindowHeight);
glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_depthBuffer);

glBindTexture(GL_TEXTURE_2D, m_finalTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, WindowWidth, WindowHeight, 0, GL_RGB, GL_FLOAT, NULL);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT4, GL_TEXTURE_2D, m_finalTexture, 0);

GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
if(status != GL_FRAMEBUFFER_COMPLETE){
    printf("[Error ] Framebuffer status: 0x%x\n", status);
    return false;
}
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
mWidth = WindowWidth;
mHeight = WindowHeight;
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
return true;

So My Question: What could be causing this? And is there a solution?

Answer 1

When I was working on my deferred renderer I was just using a texture for depth and stencil developing on an Nividia 560ti and I had no problems.But On my HD 4650 I would not show anything just a black screen so I switched to RenderBuffers for depth and stencil, and that fixed my problems.The only down side of this is that they can't be sampled in shaders. I hope this helps.

Answer 2

好吧所以我得到它的工作问题很简单我忘了在球体的渲染代码中除以sizeof（float）所以它渲染得太多甚至没有想要渲染！，但它已经修复了，所以谢谢为了帮助我获得更好的表现！