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我一直在將一些舊代碼轉換爲OpenGL 3，並且我已經完成了大部分工作。所有的VAO，VBO等工作都很好，經OpenGL調試程序驗證，我的着色器編譯得很好，但屏幕上除了清晰的顏色外沒有任何東西出現。我認爲我所有的矩陣都應該沒問題，但我不確定投影矩陣是否應該將負Z座標轉換爲正值;我試過的每個代碼示例都會生成這樣的矩陣。這裏是我的着色器：OpenGL 3程序空白屏幕
頂點着色器：
#version 330
uniform mat4 modelview;
uniform mat4 projection;
in vec4 position;
in vec4 normal;
in vec4 texCoord;
void main() {
gl_Position = projection * modelview * position;
}
片段着色器：
#version 330
out vec4 fragColor;
void main() {
fragColor = vec4(1.0, 0.0, 0.0, 1.0);
}
我的代碼是複雜的，所以我就發佈一個修改，註釋的glIntercept通話記錄的版本，它應該有所有相關的電話：
//Create shaders
glCreateShader(GL_VERTEX_SHADER)=1
glShaderSource(1,1,vertShaderText,vertShaderTextLen)
glCompileShader(1)
glGetShaderiv(1,GL_COMPILE_STATUS,buf)
glCreateShader(GL_FRAGMENT_SHADER)=2
glShaderSource(2,1,fragShaderText,fragShaderTextLen)
glCompileShader(2)
glGetShaderiv(2,GL_COMPILE_STATUS,buf)
glCreateProgram()=3
glAttachShader(3,1)
glAttachShader(3,2)
glLinkProgram(3)
glGetProgramiv(3,GL_LINK_STATUS,buf)
//Find uniform/attribute locations
//Extra glUseProgram() calls are for safety.
glGetUniformLocation(3,"modelview")=0
glUseProgram(3)
glGetUniformLocation(3,"projection")=1
glUseProgram(3)
glGetAttribLocation(3,"position")=0
glUseProgram(3)
glGetAttribLocation(3,"normal")=-1
glUseProgram(3)
glGetAttribLocation(3,"texCoord")=-1
//Create a texture; probably irrelevant to this code
glGenTextures(1,texId)
glBindTexture(GL_TEXTURE_2D,1)
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR)
glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,256,256,0,GL_RGBA,GL_UNSIGNED_BYTE,texData)
glGenTextures(1,01DD275C)
//Create VAO, VBO
glGenVertexArrays(1,vaoId)
glBindVertexArray(1)
glGenBuffers(1,bufId)
glBindBuffer(GL_ARRAY_BUFFER,1)
//Redundant call; actual data set later
glBufferData(GL_ARRAY_BUFFER,0,00000000,GL_STATIC_DRAW)
glGenBuffers(1,indexBufId)
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,4)
glBufferData(GL_ELEMENT_ARRAY_BUFFER,0,00000000,GL_STATIC_DRAW)
//Set up buffer data
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,4)
glBufferData(GL_ELEMENT_ARRAY_BUFFER,96,indexData,GL_STATIC_DRAW)
glBindBuffer(GL_ARRAY_BUFFER,1)
glBufferData(GL_ARRAY_BUFFER, 48,01DC3D00,GL_STATIC_DRAW)
//Start drawing
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT)
glUseProgram(3)
glUseProgram(3)
//Modelview
glUniformMatrix4fv(modelviewLocation,1,false,[1.000000,0.000000,0.000000,0.000000,0.000000,1.000000,0.000000,0.000000,0.000000,0.000000,1.000000,0.000000,0.000000,0.000000,-6.000000,1.000000])
glUseProgram(3)
//Projection
glUniformMatrix4fv(projectionLocation,1,false,[0.200000,0.000000,0.000000,0.000000,0.000000,0.150000,0.000000,0.000000,0.000000,0.000000,-1.000200,-1.000000,0.000000,0.000000,-0.200020,0.000000])
//Bind VAO, VBOs, and attribute positions
glBindVertexArray(1)
glBindBuffer(GL_ARRAY_BUFFER,1)
glVertexAttribPointer(positionAttributeLocation,3,GL_FLOAT,false,12,00000000)
glEnableVertexAttribArray(positionAttributeLocation)
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,4)
glDrawElements(GL_TRIANGLES,24,GL_UNSIGNED_INT,00000000) GLSL=3 Textures[ (0,2) ]
glDisableVertexAttribArray(0)
我有一架飛機直接面對c amera，但它根本沒有出現。我看到的只是清晰的顏色。剔除和深度測試已關閉。
我已經做了一些更多的調試工作;使用AMD的GPUPerfStudio，我可以驗證這些原語是由glDrawElements正確發送的，但他們永遠不會到達屏幕。我不確定什麼可以阻止他們達成目標;我盡了最大努力來驗證我所有的矩陣，甚至嘗試使用一個標識投影矩陣;似乎沒有任何工作。 – blm768 2012-07-13 00:37:44
從我所看到的片段着色器只會顯示紅色像素。那是你想要的嗎？ – user892644 2013-05-07 02:31:27