opengl对三种光源(方向光,点光源,聚光灯)进行特写并分屏渲染
分屏特写渲染效果图
实现原理
1，创建3个fbo
2,分别将方向光，点光源，聚光灯的照射效果渲染到fbo
3,在将渲染好的三个fbo作为纹理贴到要绘制的三个四边形上。
渲染入口
#include
#include "glew.h"
#include
#include
#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();
//init gpu program
GPUProgram fsqProgram;
fsqProgram.AttachShader(GL_VERTEX_SHADER, "Debug/res/shader/fullscreenquad.vs");
fsqProgram.AttachShader(GL_FRAGMENT_SHADER, "Debug/res/shader/fullscreenquad.fs");
fsqProgram.Link();
fsqProgram.DetectAttribute("pos");
fsqProgram.DetectAttribute("texcoord");
fsqProgram.DetectUniform("U_MainTexture");
GPUProgram gpuProgram;
gpuProgram.AttachShader(GL_VERTEX_SHADER, "Debug/res/shader/Light.vs");
gpuProgram.AttachShader(GL_FRAGMENT_SHADER, "Debug/res/shader/Light.fs");
gpuProgram.Link();
gpuProgram.DetectAttribute("pos");
gpuProgram.DetectAttribute("texcoord");
gpuProgram.DetectAttribute("normal");
gpuProgram.DetectUniform("M");
gpuProgram.DetectUniform("V");
gpuProgram.DetectUniform("P");
gpuProgram.DetectUniform("NM");
gpuProgram.DetectUniform("U_AmbientLightColor");
gpuProgram.DetectUniform("U_AmbientMaterial");
gpuProgram.DetectUniform("U_DiffuseLightColor");
gpuProgram.DetectUniform("U_DiffuseMaterial");
gpuProgram.DetectUniform("U_SpecularLightColor");
gpuProgram.DetectUniform("U_SpecularMaterial");
gpuProgram.DetectUniform("U_LightPos");
gpuProgram.DetectUniform("U_EyePos");
gpuProgram.DetectUniform("U_LightDirection");
gpuProgram.DetectUniform("U_Cutoff");
gpuProgram.DetectUniform("U_DiffuseIntensity");
//init 3d model
ObjModel cube;
cube.Init("Debug/res/model/Cube.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[] = { 0.2f,0.2f,0.2f,1.0f };//环境光材质
float diffuseLightColor[] = { 1.0f,1.0f,1.0f,1.0f };//漫反射光颜色
float diffuseMaterial[] = { 0.6f,0.6f,0.6f,1.0f };//漫反射光材质
float diffuseIntensity = 1.0f;//漫反射光强度
float specularLightColor[] = { 1.0f,1.0f,1.0f,1.0f };//镜面光颜色
float specularMaterial[] = { 1.0f,1.0f,1.0f,1.0f };//镜面光材质
float lightPos[] = { 0.0f,1.5f,0.0f,0.0f };//光源位置
float spotLightDirection[] = { 0.0f,-1.0f,0.0f,128.0f };//聚光灯中心线向量
float spotLightCutoff = 0.0f;//聚光灯中心线向量和入射光线最大向量
float eyePos[] = { 0.0f,0.0f,0.0f };//研究的位置
//每个渲染模型的Mode矩阵
glm::mat4 model1=glm::translate(-2.0f, 0.0f, -6.0f)*glm::rotate(-30.0f,1.0f,1.0f,1.0f);
glm::mat4 model2 = glm::translate(2.0f, 0.0f, -6.0f)*glm::rotate(-30.0f,1.0f,1.0f,1.0f);
glm::mat4 model3 = glm::translate(6.0f, 0.0f, -6.0f)*glm::rotate(-30.0f, 1.0f, 1.0f, 1.0f);
//投影矩阵
glm::mat4 projectionMatrix = glm::perspective(50.0f, (float)viewportWidth / (float)viewportHeight, 0.1f, 1000.0f);
//三个摄像机矩阵
glm::mat4 viewMatrix1 = glm::lookAt(glm::vec3(-0.5f, 1.5f, -3.0f), glm::vec3(-2.0f, 0.0f, -6.0f), glm::vec3(0.0f, 1.0f, 0.0f));
glm::mat4 viewMatrix2 = glm::lookAt(glm::vec3(3.0f, 1.5f, -3.0f), glm::vec3(2.0f, 0.0f, -6.0f), glm::vec3(0.0f, 1.0f, 0.0f));
glm::mat4 viewMatrix3 = glm::lookAt(glm::vec3(7.0f, 1.5f, -3.0f), glm::vec3(6.0f, 0.0f, -6.0f), glm::vec3(0.0f, 1.0f, 0.0f));
//法线矩阵
glm::mat4 normalMatrix1 = glm::inverseTranspose(model1);
glm::mat4 normalMatrix2 = glm::inverseTranspose(model2);
glm::mat4 normalMatrix3 = glm::inverseTranspose(model3);
FullScreenQuad fsq;
fsq.Init();
FBO fboDirectionLight;
fboDirectionLight.AttachColorBuffer("color", GL_COLOR_ATTACHMENT0, GL_RGBA, viewportWidth, viewportHeight);
fboDirectionLight.AttachDepthBuffer("depth",viewportWidth,viewportHeight);
fboDirectionLight.Finish();
FBO fboPointLight;
fboPointLight.AttachColorBuffer("color", GL_COLOR_ATTACHMENT0, GL_RGBA, viewportWidth, viewportHeight);
fboPointLight.AttachDepthBuffer("depth", viewportWidth, viewportHeight);
fboPointLight.Finish();
FBO fboSpotLight;
fboSpotLight.AttachColorBuffer("color", GL_COLOR_ATTACHMENT0, GL_RGBA, viewportWidth, viewportHeight);
fboSpotLight.AttachDepthBuffer("depth", viewportWidth, viewportHeight);
fboSpotLight.Finish();
glClearColor(41.0f / 255.0f, 71.0f / 255.0f, 121.0f / 255.0f, 1.0f);//8888
ShowWindow(hwnd, SW_SHOW);
UpdateWindow(hwnd);
glClearColor(0.0f,0.0f,0.0f,1.0f);
glEnable(GL_DEPTH_TEST);
MSG msg;
while (true)
{
if (PeekMessage(&msg, NULL, NULL, NULL, PM_REMOVE))
{
if (msg.message == WM_QUIT)
{
break;
}
TranslateMessage(&msg);
DispatchMessage(&msg);
}
//方向光的绘制绑定到fbo
fboDirectionLight.Bind();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(gpuProgram.mProgram);
//给shader中变量赋值
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);
glUniform4fv(gpuProgram.GetLocation("U_DiffuseLightColor"), 1, diffuseLightColor);
glUniform4fv(gpuProgram.GetLocation("U_DiffuseMaterial"), 1, diffuseMaterial);
glUniform4fv(gpuProgram.GetLocation("U_SpecularLightColor"), 1, specularLightColor);
glUniform4fv(gpuProgram.GetLocation("U_SpecularMaterial"), 1, specularMaterial);
glUniform3fv(gpuProgram.GetLocation("U_EyePos"), 1, eyePos);
glUniform4fv(gpuProgram.GetLocation("U_LightDirection"), 1, spotLightDirection);
glUniform1f(gpuProgram.GetLocation("U_DiffuseIntensity"), diffuseIntensity);
//指定方向光光源位置
lightPos[0] = 0.0f;
lightPos[1] = 1.5f;
lightPos[2] = 0.0f;
lightPos[3] = 0.0f;
//漫反射光强度
diffuseIntensity = 1.0f;
//聚光灯中心线和入射光线最大夹角
spotLightCutoff = 0.0f;
glUniform4fv(gpuProgram.GetLocation("U_LightPos"), 1, lightPos);
glUniform1f(gpuProgram.GetLocation("U_DiffuseIntensity"), diffuseIntensity);
glUniform1f(gpuProgram.GetLocation("U_Cutoff"), spotLightCutoff);
glUniformMatrix4fv(gpuProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(model1));
glUniformMatrix4fv(gpuProgram.GetLocation("V"), 1, GL_FALSE, glm::value_ptr(viewMatrix1));
glUniformMatrix4fv(gpuProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(normalMatrix1));
//绘制方向光光源照射的立方体
cube.Bind(gpuProgram.GetLocation("pos"), gpuProgram.GetLocation("texcoord"), gpuProgram.GetLocation("normal"));
cube.Draw();
fboDirectionLight.Unbind();//解除fbo的绑定
//点光源的绘制绑定到fbo
fboPointLight.Bind();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//指定点光源的位置
lightPos[0] = 0.0f;
lightPos[1] = 3.0f;
lightPos[2] = -6.0f;
lightPos[3] = 1.0f;
diffuseIntensity = 3.0f;
//设置shader中变量的值
glUniform4fv(gpuProgram.GetLocation("U_LightPos"), 1, lightPos);
glUniform1f(gpuProgram.GetLocation("U_DiffuseIntensity"), diffuseIntensity);
glUniformMatrix4fv(gpuProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(model2));
glUniformMatrix4fv(gpuProgram.GetLocation("V"), 1, GL_FALSE, glm::value_ptr(viewMatrix2));
glUniformMatrix4fv(gpuProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(normalMatrix2));
//绘制点光源照射的立方体
cube.Bind(gpuProgram.GetLocation("pos"), gpuProgram.GetLocation("texcoord"), gpuProgram.GetLocation("normal"));
cube.Draw();
fboPointLight.Unbind();
//聚光灯的绘制绑定到fbo
fboSpotLight.Bind();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//聚光灯光源位置
lightPos[0] = 6.3f;
lightPos[1] = 3.0f;
lightPos[2] = -5.8f;
lightPos[3] = 1.0f;
diffuseIntensity = 4.0f;
spotLightCutoff = 15.0f;
//设置shader中变量的值
glUniform4fv(gpuProgram.GetLocation("U_LightPos"), 1, lightPos);
glUniform1f(gpuProgram.GetLocation("U_DiffuseIntensity"), diffuseIntensity);
glUniform1f(gpuProgram.GetLocation("U_Cutoff"), spotLightCutoff);
glUniformMatrix4fv(gpuProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(model3));
glUniformMatrix4fv(gpuProgram.GetLocation("V"), 1, GL_FALSE, glm::value_ptr(viewMatrix3));
glUniformMatrix4fv(gpuProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(normalMatrix3));
//绘制被聚光灯照射的立方体
cube.Bind(gpuProgram.GetLocation("pos"), gpuProgram.GetLocation("texcoord"), gpuProgram.GetLocation("normal"));
cube.Draw();
fboSpotLight.Unbind();
glUseProgram(0);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);//重要，不能省略
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//切换shader,分别将三个fbo中的内容作为纹理，贴到待绘制的三个长方形上。
//将方向光fbo中的内容作为纹理贴图到左上角矩形
glUseProgram(fsqProgram.mProgram);
glActiveTexture(GL_TEXTURE0);//激活0号纹理
glBindTexture(GL_TEXTURE_2D,fboDirectionLight.GetBuffer("color"));
glUniform1i(fsqProgram.GetLocation("U_MainTexture"),0);//指定0号纹理
fsq.DrawToLeftTop(fsqProgram.GetLocation("pos"),fsqProgram.GetLocation("texcoord"));
//将点光源fbo中的内容作为纹理贴图到右上角
glBindTexture(GL_TEXTURE_2D, fboPointLight.GetBuffer("color"));
glUniform1i(fsqProgram.GetLocation("U_MainTexture"), 0);
fsq.DrawToRightTop(fsqProgram.GetLocation("pos"), fsqProgram.GetLocation("texcoord"));
//聚光灯光源fbo中的内容作为纹理贴图到左下角矩形
glBindTexture(GL_TEXTURE_2D,fboSpotLight.GetBuffer("color"));
glUniform1i(fsqProgram.GetLocation("U_MainTexture"),0);//使用0号纹理
fsq.DrawToLeftBottom(fsqProgram.GetLocation("pos"), fsqProgram.GetLocation("texcoord"));
glUseProgram(0);
glFlush();
SwapBuffers(dc);
}
return 0;
} void FullScreenQuad::DrawToLeftTop(GLint posLoc, GLint texcoordLoc)
{
//draw to left top qualter of screen
float vertices[] = {
-0.5f,0.0f,-1.0f,0.0f,0.0f,
0.0f,0.0f,-1.0f,1.0f,0.0f,
0.0f,0.5f,-1.0f,1.0f,1.0f,
-0.5f,0.5f,-1.0f,0.0f,1.0f
};
glBindBuffer(GL_ARRAY_BUFFER, mVBO);
//将顶点数据从内存上传至显卡
glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 20, vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ARRAY_BUFFER, mVBO);//绑定vbo
glEnableVertexAttribArray(posLoc);//启用顶点坐标属性
//指定顶点坐标在VBO中的起始地址
glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, sizeof(float) * 5, 0);
//启用顶点纹理属性
glEnableVertexAttribArray(texcoordLoc);
//指定纹理坐标在vbo中的起始地址
glVertexAttribPointer(texcoordLoc, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 5, (void*)(sizeof(float) * 3));
glDrawArrays(GL_QUADS, 0, 4);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}attribute vec3 pos;
attribute vec2 texcoord;
varying vec2 V_Texcoord;
void main()
{
vec4 worldPos=vec4(pos,1.0);
V_Texcoord=texcoord;
worldPos.x*=2.0;
worldPos.y*=2.0;
gl_Position=worldPos;
}