[OpenGL]Shader編譯流程示例

這裡以演示如何編譯Vertex Shader為例，其他類型的Shader類似。

1，先用io流讀取shader文件

std::stringstream code;ncode << inFile.rdbuf();ninFile.close();nstring codeStr(code.str());n

2，創建空白Shader對象

GLuint vertShader = glCreateShader( GL_VERTEX_SHADER );n

3，編譯Shader代碼到Shader對象中

// Load the source code into the shader objectnconst GLchar* codeArray[] = {codeStr.c_str()};nglShaderSource(vertShader, 1, codeArray, NULL);nn// Compile the shadernglCompileShader( fragShader );n

4，Shader鏈接

4.1 創建program對象

// Create the program objectnGLuint programHandle = glCreateProgram();n

4.2 附加Shader對象到program對象中

// Attach the shaders to the program objectnglAttachShader( programHandle, vertShader );nglAttachShader( programHandle, fragShader );n

4.3 鏈接program

// Link the programnglLinkProgram( programHandle );n

4.4 使用program對象

glUseProgram( programHandle );n

5，創建並綁定buffer對象

// Create and populate the buffer objectsnGLuint vboHandles[2];nglGenBuffers(2, vboHandles);nGLuint positionBufferHandle = vboHandles[0];nGLuint colorBufferHandle = vboHandles[1];nnglBindBuffer(GL_ARRAY_BUFFER, positionBufferHandle);nglBufferData(GL_ARRAY_BUFFER, 9 * sizeof(float), positionData, GL_STATIC_DRAW);nnglBindBuffer(GL_ARRAY_BUFFER, colorBufferHandle);nglBufferData(GL_ARRAY_BUFFER, 9 * sizeof(float), colorData, GL_STATIC_DRAW);n

6，開闢Array數組並組裝其各個元素數據

// Create and set-up the vertex array objectnglGenVertexArrays( 1, &vaoHandle );nglBindVertexArray(vaoHandle);nnglEnableVertexAttribArray(0); // Vertex positionnglEnableVertexAttribArray(1); // Vertex colornnglBindBuffer(GL_ARRAY_BUFFER, positionBufferHandle);nglVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, 0, (GLubyte *)NULL );nnglBindBuffer(GL_ARRAY_BUFFER, colorBufferHandle);nglVertexAttribPointer( 1, 3, GL_FLOAT, GL_FALSE, 0, (GLubyte *)NULL );nglBindVertexArray(0);n

推薦閱讀：