我正在尝试做基于 OpenGL GLSL 的阴影映射。问题是，在我完成了阴影贴图的渲染之后，我正在将贴图渲染到屏幕上以测试渲染是否正确，即我只是将新生成的纹理用作我要映射到屏幕上的纹理. 预期的结果是我会看到新的纹理。但相反，我看到的是一个白色区域，其纹理已绘制但非常微弱。也就是说，如果我将屏幕倾斜到某个角度，我才能看到阴影贴图的微弱轮廓。
谁能告诉我我做错了什么？
这是我的代码的相关部分：
void Init_FBO()
{
//glActiveTexture(GL_TEXTURE3);
GLfloat border[] = {1.0f, 0.0f, 0.0f, 0.0f};
glGenTextures(1, &depthTex);
glBindTexture(GL_TEXTURE_2D, depthTex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT24,900,900, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
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_CLAMP_TO_BORDER);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, border);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LESS);
glBindTexture(GL_TEXTURE_2D,0);
glGenFramebuffers(1, &shadowFBO);
glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTex, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0); // go back to the default framebuffer
// check FBO status
GLenum FBOstatus = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER);
if(FBOstatus != GL_FRAMEBUFFER_COMPLETE)
{
printf("GL_FRAMEBUFFER_COMPLETE failed, CANNOT use FBO\n");
}
else
{
printf("Frame Buffer Done Succesfully\n");
}
}
void generateShadowTex()
{
//Calculate final ligting properties
glm::vec4 a_f=light_ambient*mat_ambient;
glm::vec4 d_f=light_diffuse*mat_diffuse;
glm::vec4 s_f=light_specular*mat_specular;
int counter=0;
glEnable(GL_DEPTH_TEST); // need depth test to correctly draw 3D objects
glClearColor(0,0,0,1);
//glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glClear(GL_DEPTH_BUFFER_BIT);
glCullFace(GL_FRONT);
if(wframe)
glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
else
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
glUseProgram(programObject);
//Draw the stuff using Light Position as camera
//glutSwapBuffers();
glActiveTexture(GL_TEXTURE3);
glBindTexture(GL_TEXTURE_2D,depthTex);
glUseProgram(0);
}
void generateScene()
{
//Calculate final ligting properties
glm::vec4 a_f=light_ambient*mat_ambient;
glm::vec4 d_f=light_diffuse*mat_diffuse;
glm::vec4 s_f=light_specular*mat_specular;
int counter=0;
glEnable(GL_DEPTH_TEST); // need depth test to correctly draw 3D objects
glClearColor(0,0,0,1);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
//Draw the stuff using camera as camera position
}
glutSwapBuffers();
glUseProgram(0);
}
void display()
{
glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);
generateShadowTex();
glBindFramebuffer(GL_FRAMEBUFFER, 0);
generateScene();
}