opengl创建天空盒实现反射和折射的效果

效果图

天空盒顶点shader

attribute vec3 pos;attribute vec2 texcoord;attribute vec3 normal;uniform mat4 M;uniform mat4 P;uniform mat4 V;varying vec3 V_Texcoord;void main(){V_Texcoord=pos;gl_Position=P*V*M*vec4(pos,1.0);}

天空盒片元shader

varying vec3 V_Texcoord;uniform samplerCube U_MainTexture;void main(){gl_FragColor=textureCube(U_MainTexture,V_Texcoord);}

反射顶点shader

attribute vec3 pos;attribute vec2 texcoord;attribute vec3 normal;uniform mat4 M;uniform mat4 P;uniform mat4 V;uniform mat4 NM;varying vec4 V_WorldPos;varying vec3 V_Normal;void main(){V_WorldPos=M*vec4(pos,1.0);V_Normal=mat3(NM)*normal;//将法线坐标转换到世界空间gl_Position=P*V*M*vec4(pos,1.0);}

反射片元shader

varying vec4 V_WorldPos;varying vec3 V_Normal;uniform samplerCube U_MainTexture;void main(){//视线方向向量vec3 eyeVec=normalize(V_WorldPos.xyz-vec3(0.0));vec3 n=normalize(V_Normal);//求视线方向的反射向量vec3 r=reflect(eyeVec,n);vec4 color=textureCube(U_MainTexture,r);gl_FragColor=color;}

折射片元shader

varying vec4 V_WorldPos;varying vec3 V_Normal;uniform samplerCube U_MainTexture;void main(){vec3 eyeVec=normalize(V_WorldPos.xyz-vec3(0.0));vec3 n=normalize(V_Normal);vec3 r=refract(eyeVec,n,1.0/1.52);vec4 color=textureCube(U_MainTexture,r);gl_FragColor=color;}

渲染函数

#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);RECT rect;rect.left = 0;rect.top = 0;rect.right = 1280;rect.bottom = 720;AdjustWindowRect(&rect, WS_OVERLAPPEDWINDOW, FALSE);HWND hwnd = CreateWindowEx(NULL, L"OpenGL", L"RenderWindow", WS_OVERLAPPEDWINDOW, 100, 100, rect.right-rect.left, rect.bottom-rect.top, 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);GetClientRect(hwnd, &rect);int viewportWidth = rect.right - rect.left, viewportHeight = rect.bottom - rect.top;glewInit();GPUProgram originalProgram;originalProgram.AttachShader(GL_VERTEX_SHADER, "Debug/res/shader/skybox.vs");originalProgram.AttachShader(GL_FRAGMENT_SHADER, "Debug/res/shader/skybox.fs");originalProgram.Link();originalProgram.DetectAttribute("pos");originalProgram.DetectAttribute("texcoord");originalProgram.DetectAttribute("normal");originalProgram.DetectUniform("M");originalProgram.DetectUniform("V");originalProgram.DetectUniform("P");originalProgram.DetectUniform("U_MainTexture");GPUProgram reflectionProgram;reflectionProgram.AttachShader(GL_VERTEX_SHADER, "Debug/res/shader/reflection.vs");reflectionProgram.AttachShader(GL_FRAGMENT_SHADER, "Debug/res/shader/reflection.fs");reflectionProgram.Link();reflectionProgram.DetectAttribute("pos");reflectionProgram.DetectAttribute("texcoord");reflectionProgram.DetectAttribute("normal");reflectionProgram.DetectUniform("M");reflectionProgram.DetectUniform("V");reflectionProgram.DetectUniform("P");reflectionProgram.DetectUniform("NM");reflectionProgram.DetectUniform("U_MainTexture");GPUProgram refractionProgram;refractionProgram.AttachShader(GL_VERTEX_SHADER, "Debug/res/shader/refraction.vs");refractionProgram.AttachShader(GL_FRAGMENT_SHADER, "Debug/res/shader/refraction.fs");refractionProgram.Link();refractionProgram.DetectAttribute("pos");refractionProgram.DetectAttribute("texcoord");refractionProgram.DetectAttribute("normal");refractionProgram.DetectUniform("M");refractionProgram.DetectUniform("V");refractionProgram.DetectUniform("P");refractionProgram.DetectUniform("NM");refractionProgram.DetectUniform("U_MainTexture");//init 3d modelObjModel cube,sphere;cube.Init("Debug/res/model/Cube.obj");sphere.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};glm::mat4 cubeModel;glm::mat4 sphereModel = glm::translate(-1.5f, 0.0f, -4.0f);glm::mat4 sphereNormalMatrix = glm::inverseTranspose(sphereModel);glm::mat4 sphereModel1 = glm::translate(1.5f, 0.0f, -4.0f);glm::mat4 sphereNormalMatrix1 = glm::inverseTranspose(sphereModel1);glm::mat4 cubeNormalMatrix = glm::inverseTranspose(cubeModel);glm::mat4 projectionMatrix = glm::perspective(50.0f, (float)viewportWidth / (float)viewportHeight, 0.1f, 1000.0f);glClearColor(0.6f, 0.6f, 0.6f, 1.0f);GLuint mainTexture = SOIL_load_OGL_cubemap("Debug/res/image/right.png","Debug/res/image/left.png", "Debug/res/image/top.png", "Debug/res/image/bottom.png", "Debug/res/image/back.png", "Debug/res/image/front.png",0, 0, SOIL_FLAG_POWER_OF_TWO);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);}glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glDisable(GL_DEPTH_TEST);//normal rgbaglUseProgram(originalProgram.mProgram);glUniformMatrix4fv(originalProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(cubeModel));glUniformMatrix4fv(originalProgram.GetLocation("V"), 1, GL_FALSE, identity);glUniformMatrix4fv(originalProgram.GetLocation("P"), 1, GL_FALSE, glm::value_ptr(projectionMatrix));//绘制天空盒glBindTexture(GL_TEXTURE_CUBE_MAP, mainTexture);glUniform1i(originalProgram.GetLocation("U_MainTexture"),0);cube.Bind(originalProgram.GetLocation("pos"), originalProgram.GetLocation("texcoord"), originalProgram.GetLocation("normal"));cube.Draw();glEnable(GL_DEPTH_TEST);//绘制反射球glUseProgram(reflectionProgram.mProgram);glUniformMatrix4fv(reflectionProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(sphereModel));glUniformMatrix4fv(reflectionProgram.GetLocation("V"), 1, GL_FALSE, identity);glUniformMatrix4fv(reflectionProgram.GetLocation("P"), 1, GL_FALSE, glm::value_ptr(projectionMatrix));glUniformMatrix4fv(reflectionProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(sphereNormalMatrix));glBindTexture(GL_TEXTURE_CUBE_MAP, mainTexture);glUniform1i(reflectionProgram.GetLocation("U_MainTexture"), 0);sphere.Bind(reflectionProgram.GetLocation("pos"), reflectionProgram.GetLocation("texcoord"), reflectionProgram.GetLocation("normal"));sphere.Draw();//绘制折射球glUseProgram(refractionProgram.mProgram);glUniformMatrix4fv(refractionProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(sphereModel1));glUniformMatrix4fv(refractionProgram.GetLocation("V"), 1, GL_FALSE, identity);glUniformMatrix4fv(refractionProgram.GetLocation("P"), 1, GL_FALSE, glm::value_ptr(projectionMatrix));glUniformMatrix4fv(refractionProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(sphereNormalMatrix1));glBindTexture(GL_TEXTURE_CUBE_MAP, mainTexture);glUniform1i(refractionProgram.GetLocation("U_MainTexture"), 0);sphere.Bind(refractionProgram.GetLocation("pos"), refractionProgram.GetLocation("texcoord"), refractionProgram.GetLocation("normal"));sphere.Draw();glFlush();SwapBuffers(dc);}return 0;}