opengl光照之环境光

效果：

shader实现

顶点shader

attribute vec3 pos;//顶点坐标attribute vec2 texcoord;//纹理坐标attribute vec3 normal;//法线坐标uniform mat4 M;//模型矩阵uniform mat4 P;//投影矩阵uniform mat4 V;//摄像机观察矩阵void main(){gl_Position=P*V*M*vec4(pos,1.0);//模型中的顶点经过变换后的坐标}

片段shader

uniform vec4 U_AmbientLightColor;//环境光颜色uniform vec4 U_AmbientMaterial;////环境光材质void main(){vec4 ambientColor=U_AmbientLightColor+U_AmbientMaterial;//将颜色和材质相乘，得到最终光照颜色gl_FragColor=ambientColor;//每像素颜色}

渲染流程

#include <windows.h>#include "glew.h"#include <stdio.h>#include <math.h>#include "utils.h"#include "GPUProgram.h"#include "ObjModel.h"#include "FBO.h"#include "FullScreenQuad.h"#include "Glm/glm.hpp"#include "Glm/ext.hpp"#pragma comment(lib,"opengl32.lib")#pragma comment(lib,"glew32.lib")LRESULT CALLBACK GLWindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam){switch (msg){case WM_CLOSE:PostQuitMessage(0);break;}return DefWindowProc(hwnd,msg,wParam,lParam);}INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPSTR lpCmdLine, _In_ int nShowCmd){WNDCLASSEX wndClass;wndClass.cbClsExtra = 0;wndClass.cbSize = sizeof(WNDCLASSEX);wndClass.cbWndExtra = 0;wndClass.hbrBackground = NULL;wndClass.hCursor = LoadCursor(NULL,IDC_ARROW);wndClass.hIcon = NULL;wndClass.hIconSm = NULL;wndClass.hInstance = hInstance;wndClass.lpfnWndProc=GLWindowProc;wndClass.lpszClassName = L"OpenGL";wndClass.lpszMenuName = NULL;wndClass.style = CS_VREDRAW | CS_HREDRAW;ATOM atom = RegisterClassEx(&wndClass);HWND hwnd = CreateWindowEx(NULL, L"OpenGL", L"RenderWindow", WS_OVERLAPPEDWINDOW, 100, 100, 800, 600, NULL, NULL, hInstance, NULL);HDC dc = GetDC(hwnd);PIXELFORMATDESCRIPTOR pfd;memset(&pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));pfd.nVersion = 1;pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_TYPE_RGBA | PFD_DOUBLEBUFFER;pfd.iLayerType = PFD_MAIN_PLANE;pfd.iPixelType = PFD_TYPE_RGBA;pfd.cColorBits = 32;pfd.cDepthBits = 24;pfd.cStencilBits = 8;int pixelFormatID = ChoosePixelFormat(dc, &pfd);SetPixelFormat(dc,pixelFormatID,&pfd);HGLRC rc = wglCreateContext(dc);wglMakeCurrent(dc, rc);glewInit();//加载并编译shaderGPUProgram gpuProgram;gpuProgram.AttachShader(GL_VERTEX_SHADER, "Debug/res/shader/ambient.vs");gpuProgram.AttachShader(GL_FRAGMENT_SHADER, "Debug/res/shader/ambient.fs");gpuProgram.Link();//获取shader中对应的变量名的引用id,并将变量名，引用id作为键值对 放入mapgpuProgram.DetectAttribute("pos");gpuProgram.DetectAttribute("texcoord");gpuProgram.DetectAttribute("normal");gpuProgram.DetectUniform("M");gpuProgram.DetectUniform("V");gpuProgram.DetectUniform("P");gpuProgram.DetectUniform("U_AmbientLightColor");gpuProgram.DetectUniform("U_AmbientMaterial");//初始化并加载解析3d模型ObjModel model;model.Init("Debug/res/model/Sphere.obj");float identity[] = {1.0f,0,0,0,0,1.0f,0,0,0,0,1.0f,0,0,0,0,1.0f};float ambientLightColor[] = {0.4f,0.4f,0.4f,1.0f};//环境光颜色float ambientMaterial[] = {0.4f,0.4f,0.4f,1.0f};//环境光材质//model矩阵glm::mat4 modelMatrix = glm::translate<float>(0.0f,0.0f,-5.0f);//投影矩阵  glm::mat4 projectionMatrix = glm::perspective(50.0f, 800.0f / 600.0f, 0.1f, 1000.0f);glClearColor(41.0f/255.0f,  71.0f/255.0f, 121.0f / 255.0f, 1.0f);ShowWindow(hwnd, SW_SHOW);UpdateWindow(hwnd);MSG msg;while (true){if (PeekMessage(&msg,NULL,NULL,NULL,PM_REMOVE)){if (msg.message==WM_QUIT){break;}TranslateMessage(&msg);DispatchMessage(&msg);}glClearColor(0.0f, 0.0f, 0.0f, 1.0f);glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);glEnable(GL_DEPTH_TEST);//设置要使用的  programglUseProgram(gpuProgram.mProgram);//给gpu中变量设置值glUniformMatrix4fv(gpuProgram.GetLocation("M"), 1,GL_FALSE, glm::value_ptr(modelMatrix));glUniformMatrix4fv(gpuProgram.GetLocation("V"), 1, GL_FALSE, identity);glUniformMatrix4fv(gpuProgram.GetLocation("P"), 1, GL_FALSE, glm::value_ptr(projectionMatrix));glUniform4fv(gpuProgram.GetLocation("U_AmbientLightColor"), 1,ambientLightColor);glUniform4fv(gpuProgram.GetLocation("U_AmbientMaterial"), 1, ambientMaterial);model.Bind(gpuProgram.GetLocation("pos"), gpuProgram.GetLocation("texcoord"), gpuProgram.GetLocation("normal"));model.Draw();glUseProgram(0);glFinish();SwapBuffers(dc);}return 0;}