问题：
代码应该渲染场景并将结果写入深度纹理。当我在渲染后检查纹理的内容时，它包含所有0值。
我尝试了什么：
我尝试输出到屏幕而不是纹理，它按预期绘制场景，因此正确读取顶点和矩阵值。我已经尝试了多个教程，他们基本上都说将帧缓冲区绑定到纹理，这正是我所做的。我相信麻烦可能是某种版本问题或者我忽略的东西，如参数或其他东西。我已经在这里待了几个小时，我无法发现它。希望有人可以。
详细信息：
注意：这样做的目的是允许阴影映射工作。因此有2组着色器和绘图功能。一个绘制到深度缓冲区，另一个绘制对象。
代码：
着色器初始化代码：
void Engine::loadMObject()
{
glGenFramebuffers(1, &MObject::fbo);
glGenTextures(1, &MObject::shadowMap);
glBindFramebuffer(GL_FRAMEBUFFER, MObject::fbo);
glBindTexture(GL_TEXTURE_2D, MObject::shadowMap);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, windowWidth, windowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, MObject::shadowMap, 0);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
assi(status == GL_FRAMEBUFFER_COMPLETE, "FBO error!");
glBindFramebuffer(GL_FRAMEBUFFER, 0);
MObject::shadowProgram = Shader::compile((char*)MObject::shadowVertexShaderFile, (char*)MObject::shadowFramentShaderFile);
MObject::shadowPositionLoc = glGetAttribLocation(MObject::shadowProgram, "position");
MObject::shadowModelProjectionMatrixLoc = glGetUniformLocation(MObject::shadowProgram, "modelProjectionMatrix");
MObject::objectProgram = Shader::compile((char*)MObject::objectVertexShaderFile, (char*)MObject::objectFragmentShaderFile);
MObject::objectPositionLoc = glGetAttribLocation(MObject::objectProgram, "position");
MObject::objectTexCoordLoc = glGetAttribLocation(MObject::objectProgram, "texCoord");
MObject::objectNormalLoc = glGetAttribLocation(MObject::objectProgram, "normal");
MObject::objectWorldMatrixLoc = glGetUniformLocation(MObject::objectProgram, "worldMatrix");
MObject::objectViewMatrixLoc = glGetUniformLocation(MObject::objectProgram, "viewMatrix");
MObject::objectProjectionMatrixLoc = glGetUniformLocation(MObject::objectProgram, "projectionMatrix");
MObject::objectTextureLoc = glGetUniformLocation(MObject::objectProgram, "texture");
MObject::objectDepthModelProjectionMatrixLoc = glGetUniformLocation(MObject::objectProgram, "depthModelProjectionMatrix");
}
对象初始化代码
void Engine::load(MObject* object)
{
unload(object);
// |Physics|
object->mesh = memoryManager.alloc<btTriangleIndexVertexArray>(
object->elements.length()/3,
(int*)&object->elements[0],
3*sizeof(GLuint),
object->attributes.length(),
(btScalar*)&object->attributes[0],
sizeof(MObject::Attribute));
btCollisionShape* shape;
btScalar mass = 0;
btVector3 inertia(0, 0, 0);
if(object->dynamic)
{
shape = memoryManager.alloc<btGImpactMeshShape>(object->mesh);
((btGImpactMeshShape*)shape)->updateBound();
mass = 1;
shape->calculateLocalInertia(mass, inertia);
}else{
shape = memoryManager.alloc<btBvhTriangleMeshShape>(object->mesh, true);
}
object->rigidBody = (btRigidBody*)memoryManager.galloc(sizeof(btRigidBody), memoryManager.alignment<btRigidBody>());
new (object->rigidBody) btRigidBody(mass, object, shape, inertia); // 16-byte aligned param work around...
physicsWorld->addRigidBody(object->rigidBody);
// |Graphics|
// Vertex array object
glGenVertexArrays(1, &object->objectvao);
glBindVertexArray(object->objectvao);
// Vertex buffer object
glGenBuffers(1, &object->vbo);
glBindBuffer(GL_ARRAY_BUFFER, object->vbo);
glBufferData(GL_ARRAY_BUFFER, object->attributes.length()*sizeof(MObject::Attribute), object->attributes.data, GL_STATIC_DRAW);
// Vertex attributes
glEnableVertexAttribArray(object->objectPositionLoc);
glVertexAttribPointer(object->objectPositionLoc, 3, GL_FLOAT, GL_FALSE, sizeof(MObject::Attribute), (void*)0);
glEnableVertexAttribArray(object->objectTexCoordLoc);
glVertexAttribPointer(object->objectTexCoordLoc, 2, GL_FLOAT, GL_FALSE, sizeof(MObject::Attribute), (void*)offsetof(class MObject::Attribute, texCoord));
glEnableVertexAttribArray(object->objectNormalLoc);
glVertexAttribPointer(object->objectNormalLoc, 3, GL_SHORT, GL_TRUE, sizeof(MObject::Attribute), (void*)offsetof(class MObject::Attribute, normal));
// Element buffer object
object->eboNumElements = object->elements.length();
glGenBuffers(1, &object->ebo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, object->ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, object->elements.length()*sizeof(GLuint), object->elements.data, GL_STATIC_DRAW);
glBindVertexArray(0);
// Shadow vao
glGenVertexArrays(1, &object->shadowvao);
glBindVertexArray(object->shadowvao);
glBindBuffer(GL_ARRAY_BUFFER, object->vbo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, object->ebo);
glEnableVertexAttribArray(object->shadowPositionLoc);
glVertexAttribPointer(object->shadowPositionLoc, 3, GL_FLOAT, GL_FALSE, sizeof(MObject::Attribute), (void*)0);
glBindVertexArray(0);
mObjectList.pushBack(object);
}
绘制代码：
/ * START - 主要更新圈的部分* / // |绘制更新|
// Shadow Pass
// testing...
if(isKeyDown(SDL_SCANCODE_0)){
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(MObject::shadowProgram);
glBindFramebuffer(GL_FRAMEBUFFER, MObject::fbo);
glBindTexture(GL_TEXTURE_2D, MObject::shadowMap);
for(U32 i=0;i<mObjectList.length();++i)
{
drawShadow(mObjectList[i]);
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindTexture(GL_TEXTURE_2D, MObject::shadowMap);
GLfloat* pixels = new GLfloat[windowWidth*windowHeight];
glGetTexImage(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, GL_FLOAT, pixels);
for(U32 i=0;i<windowHeight*windowHeight;++i)
{
if(pixels[i] != 0.0f)
printd("I GOT IT!");
}
delete[] pixels;
}else{
// Object Pass
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(MObject::objectProgram);
for(U32 i=0;i<mObjectList.length();++i)
{
drawObject(mObjectList[i]);
}
}
// Swapping buffers
SDL_GL_SwapWindow(mainWindow);
/ *结束 - 主要更新圈的部分* /
void Engine::drawObject(MObject* object)
{
TransformMatrix matrix;
getOrthographicMatrix(matrix, -10, 10, 10, -10, -10, 20);
glBindVertexArray(object->objectvao);
glUniformMatrix4fv(MObject::objectWorldMatrixLoc, 1, GL_FALSE, (GLfloat*)&object->worldMatrix);
glUniformMatrix4fv(MObject::objectViewMatrixLoc, 1, GL_FALSE, (GLfloat*)&getViewMatrix());
glUniformMatrix4fv(MObject::objectProjectionMatrixLoc, 1, GL_FALSE, (GLfloat*)&getProjectionMatrix());
glUniformMatrix4fv(MObject::objectDepthModelProjectionMatrixLoc, 1, GL_FALSE, (GLfloat*)&getProjectionMatrix());
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, object->tbo);
glUniform1i(MObject::objectTextureLoc, 0);
glDrawElements(GL_TRIANGLES, object->eboNumElements, GL_UNSIGNED_INT, 0);
}
void Engine::drawShadow(MObject* object)
{
TransformMatrix matrix;
//getOrthographicMatrix(matrix, -10, 10, 10, -10, -10, 20);
matrix = getProjectionMatrix() * getViewMatrix() * object->worldMatrix;
glBindVertexArray(object->shadowvao);
glUniformMatrix4fv(MObject::shadowModelProjectionMatrixLoc, 1, GL_FALSE, (GLfloat*)&matrix);
glDrawElements(GL_TRIANGLES, object->eboNumElements, GL_UNSIGNED_INT, 0);
}
顶点着色器：
#version 140
in vec3 position;
uniform mat4 modelProjectionMatrix;
void main(){
gl_Position = modelProjectionMatrix * vec4(position, 1.0f);
}
片段着色器：
#version 140
out float fragmentdepth;
void main(){
fragmentdepth = gl_FragCoord.z;
}
/*
out vec4 color;
void main(){
color = vec4(clamp(gl_FragCoord.z, 0.0f, 1.0f), 0.0f, 0.0f, 1.0f);
}*/
答案 0 :(得分：-1)
我明白了。显然，如果你重新排列opengl调用它有点工作。我相信我所做的是将glBindFramebuffer放在glUseProgram之前并且它有效。