[英]OpenGL multiple texture with multiple shader programs
我正在嘗試在OpenGL中創建一個場景以模擬太空中的地球。 我現在有兩個球體,一個是地球,另一個是大雲。 地球和雲球對象具有自己的着色器程序,以使其簡單。 Earth shader程序采用4種紋理(白天,黑夜,specmap和Normalmap),而Cloud Shader程序采用2種紋理(cloudmap和Normalmap)。 我有一個具有render函數的對象類,在該函數中,我使用以下邏輯:
//bind the current object's texture
for (GLuint i = 0; i < texIDs.size(); i++){
glActiveTexture(GL_TEXTURE0 + i);
if (cubemap)
glBindTexture(GL_TEXTURE_CUBE_MAP, texIDs[i]);
else
glBindTexture(GL_TEXTURE_2D, texIDs[i]);
}
if (samplers.size()){
for (GLuint i = 0; i < samplers.size(); i++){
glUniform1i(glGetUniformLocation(program, samplers[i]), i);
}
}
它從第0個紋理單位開始,並將N個紋理綁定到從GL_TEXTURE0開始的N個紋理單位。 然后,它將着色器程序中的采樣器從0綁定到N。 采樣器由我在加載紋理時提供:
void Object::loadTexture(const char* filename, const GLchar* sampler){
int texID;
texID = SOIL_load_OGL_texture(filename, SOIL_LOAD_AUTO, SOIL_CREATE_NEW_ID, SOIL_FLAG_MIPMAPS | SOIL_FLAG_TEXTURE_REPEATS);
if(texID == 0){
cerr << "SOIL error: " << SOIL_last_result();
}
cout << filename << " Tex ID: " << texID << endl;
texIDs.push_back(texID);
samplers.push_back(sampler);
//glBindTexture(GL_TEXTURE_2D, texID);
}
當我這樣做時,第一個球體(地球)中的所有紋理都成功加載,但是在第二個球體中,我沒有紋理,而我只得到了一個黑色球體。 我的查詢是,如果我為每個對象使用不同的着色器程序,應該如何管理多個紋理和采樣器?
從我看到的內容來看,您正在將所有紋理綁定為單獨的紋理單元
我渲染這樣的空間物體:
我有用於特定任務的特定紋理單元
// texture units: // 0 - texture0 map 2D rgba (surface) // 1 - texture1 map 2D rgba (clouds blend) // 2 - normal map 2D xyz (normal/bump mapping) // 3 - specular map 2D i (reflection shininess) // 4 - light map 2D rgb rgb (night lights) // 5 - enviroment/skybox cube map 3D rgb
請參閱該鏈接中的着色器(它也是為太陽系可視化編寫的)...
[edit1]多重紋理的示例
// init shader once per render all geometries
GLint prog_id; // shader program ID;
GLint txrskybox; // global skybox environment cube map
GLint id;
glUseProgram(prog_id);
id=glGetUniformLocation(prog_id,"txr_texture0"); glUniform1i(id,0); //uniform sampler2D txr_texture0;
id=glGetUniformLocation(prog_id,"txr_texture1"); glUniform1i(id,1); //uniform sampler2D txr_texture1;
id=glGetUniformLocation(prog_id,"txr_normal"); glUniform1i(id,2); //uniform sampler2D txr_normal;
id=glGetUniformLocation(prog_id,"txr_specular"); glUniform1i(id,3); //uniform sampler2D txr_specular;
id=glGetUniformLocation(prog_id,"txr_light"); glUniform1i(id,4); //uniform sampler2D txr_light;
id=glGetUniformLocation(prog_id,"txr_skybox"); glUniform1i(id,5); //uniform samplerCube txr_skybox;
// add here all uniforms you need ...
glActiveTexture(GL_TEXTURE0+5); glEnable(GL_TEXTURE_CUBE_MAP); glBindTexture(GL_TEXTURE_CUBE_MAP,txrskybox);
for (i=0;i<all_objects;i++)
{
// add here all uniforms you need ...
// pass textures once per any object render
// obj::(GLint) txr0,txr1,txrnor,txrspec,txrlight; // object local textures
glActiveTexture(GL_TEXTURE0+0); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D,obj[i].txr0);
glActiveTexture(GL_TEXTURE0+1); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D,obj[i].txr1);
glActiveTexture(GL_TEXTURE0+2); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D,obj[i].txrnor);
glActiveTexture(GL_TEXTURE0+3); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D,obj[i].txrspec);
glActiveTexture(GL_TEXTURE0+4); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D,obj[i].txrlight);
// here render the geometry of obj[i]
}
// unbind textures and shaders
glActiveTexture(GL_TEXTURE0+5); glBindTexture(GL_TEXTURE_CUBE_MAP,0); glDisable(GL_TEXTURE_CUBE_MAP);
glActiveTexture(GL_TEXTURE0+4); glBindTexture(GL_TEXTURE_2D,0); glDisable(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0+3); glBindTexture(GL_TEXTURE_2D,0); glDisable(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0+2); glBindTexture(GL_TEXTURE_2D,0); glDisable(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0+1); glBindTexture(GL_TEXTURE_2D,0); glDisable(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0+0); glBindTexture(GL_TEXTURE_2D,0); glDisable(GL_TEXTURE_2D); // unit0 at last so it stays active ...
glUseProgram(0);
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