目录
前言
上一篇文章回顾:OpenGL学习(十)天空盒
上一次更新还是元旦了,因为最近一直忙于期末考试的预习,考完玩了几天,昨天才 run 回家,今天开始更新!
在这之前的博客,我们都是使用 “前向渲染” 来对生成的像素做处理,比如我们可以为每一个像素添加光照,阴影等效果。但是今天我们要引入一种更加高级的渲染方式 ---- 延迟渲染。
注:本文代码基于上一篇博客
延迟渲染简介
延迟渲染是各大计算机游戏引擎常用的一种较为现代的渲染策略,延迟渲染的出现最主要是为了解决了大量光源的光照计算,减少了片元着色器的计算量,使得渲染复杂的场景变得可能!
回顾我们的 OpenGL 的流水线,我们在对三角面片进行光栅化之后,马上生成像素,并且 call GPU 的一个线程,对该像素运行一次片段着色器。这并未考虑到物体之间的遮挡关系!如果此时有另一片三角面片也绘制在同样的地方,前一个三角型的像素就会被遮挡,浪费片段着色器计算力。示意图如下:
如果场景非常复杂,那么我们会有多重的覆盖关系,那么片元着色器将会被运行很多次。对于一些复杂计算,比如计算光照,阴影等开销大的算法,无效的片元开销是致命的。
延迟渲染的出现解决了这个问题。以光照计算为例,回想我们计算光照需要那些信息?
- 当前像素的世界坐标
- 当前像素的法线
- 当前像素的颜色
那么我们将这些信息先输出到一些纹理上存储起来,随后绘制一个正方形当作我们的 “屏幕”,然后针对每个屏幕上的像素,从纹理中取出需要的颜色,法线,坐标等信息,再进行光照计算。这样无论场景有多么复杂,我们都只需要运行 w × h 次片元着色器,其中 w,h 为屏幕宽高,绝不浪费宝贵的光照计算。
下面是一个典型的延迟渲染管线的大概结构:
首先是 shadowMap 阶段,我们从光源方向进行渲染,获得阴影贴图。gbuffer 阶段我们正常地渲染,但是不输出颜色,反之我们输出必要的信息到纹理。在后处理阶段我们绘制光影特效,最终输出一帧。
注:
一般后处理着色器可以有很多个,因为要对一些像素做多次 pass,比如计算泛光或者 SSR 等特效
此外,针对多个后处理着色器的管线,我们可以创建一个后处理帧缓冲和多个颜色附件,然后按照顺序将必要的纹理 pass 下去,那么该管线就和 Minecraft 的 optifine 模组提供的管线相似了。
即然提到了 MC 就多嗦两句 p 话:
optifine 提供了 10 个后处理阶段的自定义着色器(composite0 ~ 9)和一个最终合成阶段着色器(final),final 着色器总是工作在后处理阶段之后,用来进行不同帧缓冲数据合成。此外,optifine允许用户任意地操作 8 个颜色纹理附件,但是最终 0 号颜色附件会被输出到屏幕。
变量创建与准备
因为 gbuffer 阶段的渲染需要一些纹理以缓存,我们定义:
- gcolor 存储基础颜色
- gdepth 存储像素的深度
- gworldpos 存储像素的世界坐标
- gnormal 存储像素的法向量
我们创建如下的全局变量,同时生成对应的着色器:
// 延迟渲染阶段
GLuint gbufferProgram;
GLuint gbufferFBO; // gbuffer 阶段帧缓冲
GLuint gcolor; // 基本颜色纹理
GLuint gdepth; // 深度纹理
GLuint gworldpos; // 世界坐标纹理
GLuint gnormal; // 法线纹理
// 后处理阶段
GLuint composite0;
...
// 生成着色器程序对象
gbufferProgram = getShaderProgram("shaders/gbuffer.fsh", "shaders/gbuffer.vsh");
shadowProgram = getShaderProgram("shaders/shadow.fsh", "shaders/shadow.vsh");
debugProgram = getShaderProgram("shaders/debug.fsh", "shaders/debug.vsh");
skyboxProgram = getShaderProgram("shaders/skybox.fsh", "shaders/skybox.vsh");
composite0 = getShaderProgram("shaders/composite0.fsh", "shaders/composite0.vsh");
其中着色器和他们所属的阶段如下:
随后我们创建一个 gubffer 的帧缓冲,并且指定 3 个颜色附件和一个深度附件,用于存储必要的信息:
// 创建 gubffer 帧缓冲
glGenFramebuffers(1, &gbufferFBO);
glBindFramebuffer(GL_FRAMEBUFFER, gbufferFBO);
// 创建颜色纹理
glGenTextures(1, &gcolor);
glBindTexture(GL_TEXTURE_2D, gcolor);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, windowWidth, windowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将颜色纹理绑定到 0 号颜色附件
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, gcolor, 0);
// 创建法线纹理
glGenTextures(1, &gnormal);
glBindTexture(GL_TEXTURE_2D, gnormal);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, windowWidth, windowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将法线纹理绑定到 1 号颜色附件
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, gnormal, 0);
// 创建世界坐标纹理
glGenTextures(1, &gworldpos);
glBindTexture(GL_TEXTURE_2D, gworldpos);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, windowWidth, windowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将世界坐标纹理绑定到 2 号颜色附件
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, GL_TEXTURE_2D, gworldpos, 0);
// 创建深度纹理
glGenTextures(1, &gdepth);
glBindTexture(GL_TEXTURE_2D, gdepth);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, windowWidth, windowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将深度纹理绑定到深度附件
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, gdepth, 0);
// 指定附件索引
GLuint attachments[3] = {
GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2 };
glDrawBuffers(3, attachments);
glBindFramebuffer(GL_FRAMEBUFFER, 0); // 解绑
注意到 glDrawBuffers 函数指定的附件绘制顺序,即是着色器中 gl_FragData
的索引,比如 gl_FragData[0]
对应的是 attachments[0]
,也就是我们的颜色纹理附件!执行如下的操作能向 0 号纹理附件中进行写入一块红色:
gl_FragData[0] = vec4(1, 0, 0, 1);
注:
其实没有必要生成世界坐标纹理,因为可以通过深度纹理和当前像素的屏幕坐标,重建其世界坐标。
Minecraft 的光影模组 optifine 就是这么操作的,但是缺点是必须知道 模型-视图矩阵的逆矩阵
这里我懒得算了,干脆直接缓存世界坐标来用了。。。
shadowMap 阶段
shadowMap 阶段和往常一样,我们正常进行绘制即可,因为最终我们需要的只是一张阴影贴图:
display 函数
...
// 从光源方向进行渲染
glUseProgram(shadowProgram);
glBindFramebuffer(GL_FRAMEBUFFER, shadowMapFBO);
glClear(GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, shadowMapResolution, shadowMapResolution);
// 光源看向世界坐标原点
shadowCamera.direction = glm::normalize(glm::vec3(0, 0, 0) - shadowCamera.position);
// 传视图矩阵
...
// 传投影矩阵
...
// 从光源方向进行绘制
for (auto m : models)
{
m.draw(shadowProgram);
}
gbuffer 阶段
在 gbuffer 阶段,我们分两个着色器进行绘制。skybox 着色器负责绘制天空盒,而 gbuffer 着色器负责绘制一般物体。所以我们要进行两次 draw call,代码如下:
display 函数
...
// 绘制天空盒 -- 输出到 gbuffer 阶段的 3 张纹理中
glUseProgram(skyboxProgram);
glBindFramebuffer(GL_FRAMEBUFFER, gbufferFBO);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, windowWidth, windowHeight);
// 传视图,投影矩阵
...
// 传cubemap纹理
...
// 传递 zfar 和 znear 方便让天空盒的坐标置于最大视距
...
glDepthMask(GL_FALSE);
skybox.draw(skyboxProgram);
glDepthMask(GL_TRUE);
// ------------------------------------------------------------------------ //
// 正常绘制 -- 输出到 gbuffer 阶段的 3 张纹理中
glUseProgram(gbufferProgram);
// 传视图矩阵
...
// 传投影矩阵
...
// 正常绘制
for (auto m : models)
{
m.draw(gbufferProgram);
}
值得注意的是,片元着色器不再输出颜色了,反而是输出几何信息到我们的纹理缓存中,下面是 gbuffer.fsh 片元着色器的代码:
#version 330 core
...
void main()
{
gl_FragData[0] = texture2D(texture, texcoord); // 写入 gcolor
gl_FragData[1] = vec4(normalize(normal), 0.0); // 写入 gnormal
gl_FragData[2] = vec4(worldPos, 1.0); // 写入 gworldpos
}
对于 skybox 天空盒的绘制则比较特殊,因为天空盒不参与光照阴影的计算,于是我们在其世界坐标中给他一个很大的值,这里利用了透视投影摄像机的 far 参数,我们将天空的距离拉扯至两倍的远截面:
#version 330 core
...
uniform float far;
void main()
{
gl_FragData[0] = textureCube(skybox, texcoord); // 写入 gcolor
gl_FragData[1] = vec4(vec3(0), 0.0); // 写入 gnormal
gl_FragData[2] = vec4(texcoord*far*2, 1.0); // 写入 gworldpos
}
后处理阶段
我们只需要绘制一个四边形,并且让他铺满屏幕即可。此外,我们传递 gbuffer 阶段绘制的必要的几何信息(就是那些纹理),代码如下:
display 函数
...
// debug着色器输出一个四方形以显示纹理中的数据
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glDisable(GL_DEPTH_TEST); // 需要取消深度测试以保证其覆盖在原画面上
glUseProgram(debugProgram);
glViewport(0, 0, windowWidth, windowHeight);
// 传递 zfar 和 znear 方便转线性深度
...
// 传 gcolor 纹理
...
// 传 gnormal 纹理
...
// 传 gworldpos 纹理
...
// 传 gdepth 纹理
...
// 传阴影深度纹理
...
// 绘制
screen.draw(debugProgram);
glEnable(GL_DEPTH_TEST);
随后我们在着色器中,根据屏幕坐标取 4 个纹理中不同的数据,并且打印在屏幕上,下面是 debug 着色器的代码:
#version 330 core
...
void main()
{
// 屏幕左下显示 gcolor
if(0<=texcoord.x && texcoord.x<=0.5 && 0<=texcoord.y && texcoord.y<=0.5)
{
vec2 coord = vec2(texcoord.x*2, texcoord.y*2);
fColor = vec4(texture2D(gcolor, coord).rgb, 1);
}
// 屏幕右下显示 gnormal
if(0.5<=texcoord.x && texcoord.x<=1 && 0<=texcoord.y && texcoord.y<=0.5)
{
vec2 coord = vec2(texcoord.x*2-1, texcoord.y*2);
fColor = vec4(texture2D(gnormal, coord).rgb, 1);
}
// 屏幕左上显示 gdepth
if(0<=texcoord.x && texcoord.x<=0.5 && 0.5<=texcoord.y && texcoord.y<=1)
{
vec2 coord = vec2(texcoord.x*2, texcoord.y*2-1);
float d = linearizeDepth(texture2D(gdepth, coord).r, near, far);
//d = texture2D(shadowtex, coord).r;
fColor = vec4(vec3(d*0.5+0.5), 1);
}
// 屏幕右上显示 gworldpos
if(0.5<=texcoord.x && texcoord.x<=1 && 0.5<=texcoord.y && texcoord.y<=1)
{
vec2 coord = vec2(texcoord.x*2-1, texcoord.y*2-1);
fColor = vec4(texture2D(gworldpos, coord).rgb, 1);
}
}
效果如下:
可以看到 4 个纹理的数据都正常。现在我们开始进行光影的绘制,我们编写 composite0 着色器,片段着色器的内容如下:
#version 330 core
...
void main()
{
fColor.rgb = texture2D(gcolor, texcoord).rgb;
vec3 worldPos = texture2D(gworldpos, texcoord).xyz;
vec3 normal = texture2D(gnormal, texcoord).xyz;
float isInShadow = shadowMapping(shadowtex, shadowVP, vec4(worldPos, 1.0));
PhongStruct phong = phong(worldPos, cameraPos, lightPos, normal);
// 如果在阴影中则只有环境光
if(isInShadow==0) {
fColor.rgb *= phong.ambient + phong.diffuse + phong.specular;
} else if(isInShadow==1.0) {
fColor.rgb *= phong.ambient; // only ambient
}
}
注意这里我们使用了一个小 trick,因为天空盒不属于阴影和光照计算的物体,于是我们通过判断其是否在光源摄像机的视野中,就可以知道它是否是天空盒。判断的代码如下:
// 阴影映射
float shadowMapping(sampler2D tex, mat4 shadowVP, vec4 worldPos) {
// 转换到光源坐标
vec4 lightPos = shadowVP * worldPos;
lightPos = vec4(lightPos.xyz/lightPos.w, 1.0);
lightPos = lightPos*0.5 + 0.5;
// 超出阴影贴图视野 -- 返回一个特殊值
if(lightPos.x<0 || lightPos.x>1 || lightPos.y<0 || lightPos.y>1 || lightPos.z<0 || lightPos.z>1) {
return 2.0;
}
// 计算shadowmapping
float closestDepth = texture2D(tex, lightPos.xy).r; // shadowmap中最近点的深度
float currentDepth = lightPos.z; // 当前点的深度
float isInShadow = (currentDepth>closestDepth+0.005) ? (1.0) : (0.0);
return isInShadow;
}
然后我们和 debug 着色器类似,也是传纹理,传 uniform,然后 draw call,使用 comopiste0 着色器进行绘制。现在来看 c++ 的代码:
display 函数
...
// 后处理阶段: composite0 着色器进行渲染
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glDisable(GL_DEPTH_TEST);
glUseProgram(composite0);
glViewport(0, 0, windowWidth, windowHeight);
// 传递 zfar 和 znear 方便转线性深度
...
// 传 gcolor 纹理
...
// 传 gnormal 纹理
...
// 传 gworldpos 纹理
...
// 传 gdepth 纹理
...
// 传阴影深度纹理
...
// 传递矩阵: 转换到光源坐标的变换矩阵
...
// 传递光源位置
...
// 传递相机位置
...
// 绘制
screen.draw(composite0);
glEnable(GL_DEPTH_TEST);
最终效果:
你可能会说这和之前的有啥区别啊?是的,图像没有任何区别,但是我们使用了截然不同的策略进行渲染。在后续的博客中,会基于延迟渲染,进行一些令人赛艇的特效的编写。。。
篇幅有限,本来还想进行多光源渲染的对比,无奈篇幅有限,下次一定!
完整代码
着色器
shadow
顶点着色器代码(.vsh文件):
#version 330 core
layout (location = 0) in vec3 vPosition;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection * view * model * vec4(vPosition, 1.0);
}
片元着色器代码(.fsh文件):
#version 330 core
void main()
{
// gl_FragDepth = gl_FragCoord.z;
}
skybox
顶点着色器代码(.vsh文件):
#version 330 core
// 顶点着色器输入
layout (location = 0) in vec3 vPosition;
out vec3 texcoord;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection * view * model * vec4(vPosition, 1.0);
texcoord = vPosition; // 坐标作为cubeMap采样坐标
}
片元着色器代码(.fsh文件):
#version 330 core
in vec3 texcoord;
uniform samplerCube skybox;
// 透视投影近截面 / 远截面
uniform float near;
uniform float far;
void main()
{
gl_FragData[0] = textureCube(skybox, texcoord); // 写入 gcolor
gl_FragData[1] = vec4(vec3(0), 0.0); // 写入 gnormal
gl_FragData[2] = vec4(texcoord*far*2, 1.0); // 写入 gworldpos
}
gbuffer
顶点着色器代码(.vsh文件):
#version 330 core
// 顶点着色器输入
layout (location = 0) in vec3 vPosition;
layout (location = 1) in vec2 vTexcoord;
layout (location = 2) in vec3 vNormal;
out vec3 worldPos;
out vec2 texcoord;
out vec3 normal;
uniform mat4 model; // 模型变换矩阵
uniform mat4 view; // 模型变换矩阵
uniform mat4 projection; // 模型变换矩阵
void main()
{
gl_Position = projection * view * model * vec4(vPosition, 1.0);
// 传递到片段着色器
texcoord = vTexcoord;
worldPos = (model * vec4(vPosition, 1.0)).xyz;
normal = (model * vec4(vNormal, 0.0)).xyz;
}
片元着色器代码(.fsh文件):
#version 330 core
in vec3 worldPos; // 当前片元的世界坐标
in vec2 texcoord; // 纹理坐标
in vec3 normal; // 法向量
uniform sampler2D texture;
void main()
{
gl_FragData[0] = texture2D(texture, texcoord); // 写入 gcolor
gl_FragData[1] = vec4(normalize(normal), 0.0); // 写入 gnormal
gl_FragData[2] = vec4(worldPos, 1.0); // 写入 gworldpos
}
debug
顶点着色器代码(.vsh文件):
#version 330 core
// 顶点着色器输入
layout (location = 0) in vec3 vPosition;
layout (location = 1) in vec2 vTexcoord;
// 传给片元着色器的变量
out vec2 texcoord;
void main()
{
gl_Position = vec4(vPosition, 1.0);
texcoord = vTexcoord;
}
片元着色器代码(.fsh文件):
#version 330 core
in vec2 texcoord;
out vec4 fColor;
// 纹理数据
uniform sampler2D gcolor;
uniform sampler2D gnormal;
uniform sampler2D gdepth;
uniform sampler2D gworldpos;
uniform sampler2D shadowtex; // shadow纹理
uniform float near;
uniform float far;
// 屏幕深度转线性深度
float linearizeDepth(float depth, float near, float far) {
return (2.0 * near) / (far + near - depth * (far - near));
}
void main()
{
// 屏幕左下显示 gcolor
if(0<=texcoord.x && texcoord.x<=0.5 && 0<=texcoord.y && texcoord.y<=0.5)
{
vec2 coord = vec2(texcoord.x*2, texcoord.y*2);
fColor = vec4(texture2D(gcolor, coord).rgb, 1);
}
// 屏幕右下显示 gnormal
if(0.5<=texcoord.x && texcoord.x<=1 && 0<=texcoord.y && texcoord.y<=0.5)
{
vec2 coord = vec2(texcoord.x*2-1, texcoord.y*2);
fColor = vec4(texture2D(gnormal, coord).rgb, 1);
}
// 屏幕左上显示 gdepth
if(0<=texcoord.x && texcoord.x<=0.5 && 0.5<=texcoord.y && texcoord.y<=1)
{
vec2 coord = vec2(texcoord.x*2, texcoord.y*2-1);
float d = linearizeDepth(texture2D(gdepth, coord).r, near, far);
//d = texture2D(shadowtex, coord).r;
fColor = vec4(vec3(d*0.5+0.5), 1);
}
// 屏幕右上显示 gworldpos
if(0.5<=texcoord.x && texcoord.x<=1 && 0.5<=texcoord.y && texcoord.y<=1)
{
vec2 coord = vec2(texcoord.x*2-1, texcoord.y*2-1);
fColor = vec4(texture2D(gworldpos, coord).rgb, 1);
}
}
conposite0
顶点着色器代码(.vsh文件):
#version 330 core
// 顶点着色器输入
layout (location = 0) in vec3 vPosition;
layout (location = 1) in vec2 vTexcoord;
// 传给片元着色器的变量
out vec2 texcoord;
void main()
{
gl_Position = vec4(vPosition, 1.0);
texcoord = vTexcoord;
}
片元着色器代码(.fsh文件):
#version 330 core
in vec2 texcoord;
out vec4 fColor;
// 纹理数据
uniform sampler2D gcolor;
uniform sampler2D gnormal;
uniform sampler2D gdepth;
uniform sampler2D gworldpos;
uniform sampler2D shadowtex; // shadow纹理
// 透视投影近截面 / 远截面
uniform float near;
uniform float far;
uniform mat4 shadowVP; // 转换到光源坐标的变换矩阵
uniform vec3 lightPos; // 光源位置
uniform vec3 cameraPos; // 相机位置
// 屏幕深度转线性深度
float linearizeDepth(float depth, float near, float far) {
return (2.0 * near) / (far + near - depth * (far - near));
}
// 阴影映射
float shadowMapping(sampler2D tex, mat4 shadowVP, vec4 worldPos) {
// 转换到光源坐标
vec4 lightPos = shadowVP * worldPos;
lightPos = vec4(lightPos.xyz/lightPos.w, 1.0);
lightPos = lightPos*0.5 + 0.5;
// 超出阴影贴图视野 -- 返回一个特殊值
if(lightPos.x<0 || lightPos.x>1 || lightPos.y<0 || lightPos.y>1 || lightPos.z<0 || lightPos.z>1) {
return 2.0;
}
// 计算shadowmapping
float closestDepth = texture2D(tex, lightPos.xy).r; // shadowmap中最近点的深度
float currentDepth = lightPos.z; // 当前点的深度
float isInShadow = (currentDepth>closestDepth+0.005) ? (1.0) : (0.0);
return isInShadow;
}
// phong 光照计算
struct PhongStruct
{
float ambient;
float diffuse;
float specular;
};
PhongStruct phong(vec3 worldPos, vec3 cameraPos, vec3 lightPos, vec3 normal)
{
vec3 N = normalize(normal);
vec3 V = normalize(worldPos - cameraPos);
vec3 L = normalize(worldPos - lightPos);
vec3 R = reflect(L, N);
PhongStruct phong;
phong.ambient = 0.3;
phong.diffuse = max(dot(N, -L), 0);
phong.specular = pow(max(dot(-R, V), 0), 50.0) * 1.1;
return phong;
}
void main()
{
fColor.rgb = texture2D(gcolor, texcoord).rgb;
vec3 worldPos = texture2D(gworldpos, texcoord).xyz;
vec3 normal = texture2D(gnormal, texcoord).xyz;
float isInShadow = shadowMapping(shadowtex, shadowVP, vec4(worldPos, 1.0));
PhongStruct phong = phong(worldPos, cameraPos, lightPos, normal);
// 如果在阴影中则只有环境光
if(isInShadow==0) {
fColor.rgb *= phong.ambient + phong.diffuse + phong.specular;
} else if(isInShadow==1.0) {
fColor.rgb *= phong.ambient; // only ambient
}
}
c++
// std c++
#include <iostream>
#include <string>
#include <fstream>
#include <vector>
#include <map>
#include <sstream>
#include <iostream>
// glew glut
#include <GL/glew.h>
#include <GL/freeglut.h>
// glm
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
// SOIL
#include <SOIL2/SOIL2.h>
// assimp
#include <assimp/Importer.hpp>
#include <assimp/scene.h>
#include <assimp/postprocess.h>
// --------------------- end of include --------------------- //
class Mesh
{
public:
// OpenGL 对象
GLuint vao, vbo, ebo;
GLuint diffuseTexture; // 漫反射纹理
// 顶点属性
std::vector<glm::vec3> vertexPosition;
std::vector<glm::vec2> vertexTexcoord;
std::vector<glm::vec3> vertexNormal;
// glDrawElements 函数的绘制索引
std::vector<int> index;
Mesh() {
}
void bindData()
{
// 创建顶点数组对象
glGenVertexArrays(1, &vao); // 分配1个顶点数组对象
glBindVertexArray(vao); // 绑定顶点数组对象
// 创建并初始化顶点缓存对象 这里填NULL 先不传数据
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER,
vertexPosition.size() * sizeof(glm::vec3) +
vertexTexcoord.size() * sizeof(glm::vec2) +
vertexNormal.size() * sizeof(glm::vec3),
NULL, GL_STATIC_DRAW);
// 传位置
GLuint offset_position = 0;
GLuint size_position = vertexPosition.size() * sizeof(glm::vec3);
glBufferSubData(GL_ARRAY_BUFFER, offset_position, size_position, vertexPosition.data());
glEnableVertexAttribArray(0); // 着色器中 (layout = 0) 表示顶点位置
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid*)(offset_position));
// 传纹理坐标
GLuint offset_texcoord = size_position;
GLuint size_texcoord = vertexTexcoord.size() * sizeof(glm::vec2);
glBufferSubData(GL_ARRAY_BUFFER, offset_texcoord, size_texcoord, vertexTexcoord.data());
glEnableVertexAttribArray(1); // 着色器中 (layout = 1) 表示纹理坐标
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, (GLvoid*)(offset_texcoord));
// 传法线
GLuint offset_normal = size_position + size_texcoord;
GLuint size_normal = vertexNormal.size() * sizeof(glm::vec3);
glBufferSubData(GL_ARRAY_BUFFER, offset_normal, size_normal, vertexNormal.data());
glEnableVertexAttribArray(2); // 着色器中 (layout = 2) 表示法线
glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid*)(offset_normal));
// 传索引到 ebo
glGenBuffers(1, &ebo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, index.size() * sizeof(GLuint), index.data(), GL_STATIC_DRAW);
glBindVertexArray(0);
}
void draw(GLuint program)
{
glBindVertexArray(vao);
// 传纹理
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, diffuseTexture);
glUniform1i(glGetUniformLocation(program, "texture"), 0);
// 绘制
glDrawElements(GL_TRIANGLES, this->index.size(), GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
}
};
class Model
{
public:
std::vector<Mesh> meshes;
std::map<std::string, GLuint> textureMap;
glm::vec3 translate = glm::vec3(0, 0, 0), rotate = glm::vec3(0, 0, 0), scale = glm::vec3(1, 1, 1);
Model() {
}
void load(std::string filepath)
{
Assimp::Importer import;
const aiScene* scene = import.ReadFile(filepath, aiProcess_Triangulate | aiProcess_FlipUVs);
// 异常处理
if (!scene || scene->mFlags == AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode)
{
std::cout << "读取模型出现错误: " << import.GetErrorString() << std::endl;
exit(-1);
}
// 模型文件相对路径
std::string rootPath = filepath.substr(0, filepath.find_last_of('/'));
// 循环生成 mesh
for (int i = 0; i < scene->mNumMeshes; i++)
{
// 引用当前mesh
meshes.push_back(Mesh());
Mesh& mesh = meshes.back();
// 获取 assimp 的读取到的 aimesh 对象
aiMesh* aimesh = scene->mMeshes[i];
// 我们将数据传递给我们自定义的mesh
for (int j = 0; j < aimesh->mNumVertices; j++)
{
// 顶点
glm::vec3 vvv;
vvv.x = aimesh->mVertices[j].x;
vvv.y = aimesh->mVertices[j].y;
vvv.z = aimesh->mVertices[j].z;
mesh.vertexPosition.push_back(vvv);
// 法线
vvv.x = aimesh->mNormals[j].x;
vvv.y = aimesh->mNormals[j].y;
vvv.z = aimesh->mNormals[j].z;
mesh.vertexNormal.push_back(vvv);
// 纹理坐标: 如果存在则加入。assimp 默认可以有多个纹理坐标 我们取第一个(0)即可
glm::vec2 vv(0, 0);
if (aimesh->mTextureCoords[0])
{
vv.x = aimesh->mTextureCoords[0][j].x;
vv.y = aimesh->mTextureCoords[0][j].y;
}
mesh.vertexTexcoord.push_back(vv);
}
// 如果有材质,那么传递材质
if (aimesh->mMaterialIndex >= 0)
{
// 获取当前 aimesh 的材质对象
aiMaterial* material = scene->mMaterials[aimesh->mMaterialIndex];
// 获取 diffuse 贴图文件路径名称 我们只取1张贴图 故填 0 即可
aiString aistr;
material->GetTexture(aiTextureType_DIFFUSE, 0, &aistr);
std::string texpath = aistr.C_Str();
texpath = rootPath + '/' + texpath; // 取相对路径
// 如果没生成过纹理,那么生成它
if (textureMap.find(texpath) == textureMap.end())
{
// 生成纹理
GLuint tex;
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
int textureWidth, textureHeight;
unsigned char* image = SOIL_load_image(texpath.c_str(), &textureWidth, &textureHeight, 0, SOIL_LOAD_RGB);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, textureWidth, textureHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, image); // 生成纹理
delete[] image;
textureMap[texpath] = tex;
}
// 传递纹理
mesh.diffuseTexture = textureMap[texpath];
}
// 传递面片索引
for (GLuint j = 0; j < aimesh->mNumFaces; j++)
{
aiFace face = aimesh->mFaces[j];
for (GLuint k = 0; k < face.mNumIndices; k++)
{
mesh.index.push_back(face.mIndices[k]);
}
}
mesh.bindData();
}
}
void draw(GLuint program)
{
// 传模型矩阵
glm::mat4 unit( // 单位矩阵
glm::vec4(1, 0, 0, 0),
glm::vec4(0, 1, 0, 0),
glm::vec4(0, 0, 1, 0),
glm::vec4(0, 0, 0, 1)
);
glm::mat4 scale = glm::scale(unit, this->scale);
glm::mat4 translate = glm::translate(unit, this->translate);
glm::mat4 rotate = unit; // 旋转
rotate = glm::rotate(rotate, glm::radians(this->rotate.x), glm::vec3(1, 0, 0));
rotate = glm::rotate(rotate, glm::radians(this->rotate.y), glm::vec3(0, 1, 0));
rotate = glm::rotate(rotate, glm::radians(this->rotate.z), glm::vec3(0, 0, 1));
// 模型变换矩阵
glm::mat4 model = translate * rotate * scale;
GLuint mlocation = glGetUniformLocation(program, "model"); // 名为model的uniform变量的位置索引
glUniformMatrix4fv(mlocation, 1, GL_FALSE, glm::value_ptr(model)); // 列优先矩阵
for (int i = 0; i < meshes.size(); i++)
{
meshes[i].draw(program);
}
}
};
class Camera
{
public:
// 相机参数
glm::vec3 position = glm::vec3(0, 0, 0); // 位置
glm::vec3 direction = glm::vec3(0, 0, -1); // 视线方向
glm::vec3 up = glm::vec3(0, 1, 0); // 上向量,固定(0,1,0)不变
float pitch = 0.0f, roll = 0.0f, yaw = 0.0f; // 欧拉角
float fovy = 70.0f, aspect = 1.0, zNear = 0.01, zFar = 100; // 透视投影参数
float left = -1.0, right = 1.0, top = 1.0, bottom = -1.0; // 正交投影参数
Camera() {
}
// 视图变换矩阵
glm::mat4 getViewMatrix(bool useEulerAngle = true)
{
if (useEulerAngle) // 使用欧拉角更新相机朝向
{
direction.x = cos(glm::radians(pitch)) * sin(glm::radians(yaw));
direction.y = sin(glm::radians(pitch));
direction.z = -cos(glm::radians(pitch)) * cos(glm::radians(yaw)); // 相机看向z轴负方向
}
return glm::lookAt(position, position + direction, up);
}
// 投影矩阵
glm::mat4 getProjectionMatrix(bool usePerspective = true)
{
if (usePerspective) // 透视投影
{
return glm::perspective(glm::radians(fovy), aspect, zNear, zFar);
}
return glm::ortho(left, right, bottom, top, zNear, zFar);
}
};
// ---------------------------- end of class definition ---------------------------- //
// 模型
std::vector<Model> models; // 场景
Model screen; // 渲染一个四方形做屏幕
Model skybox; // 渲染一个立方体用于立方体贴图绘制天空盒
// 着色器程序对象
GLuint program;
GLuint debugProgram; // 调试用
GLuint shadowProgram; // 绘制阴影的着色器程序对象
GLuint skyboxProgram; // 天空盒绘制
// 纹理
GLuint skyboxTexture; // 天空盒
GLuint shadowTexture; // 阴影纹理
// 相机
Camera camera; // 正常渲染
Camera shadowCamera; // 从光源方向渲染
// 光源与阴影参数
int shadowMapResolution = 1024; // 阴影贴图分辨率
GLuint shadowMapFBO; // 从光源方向进行渲染的帧缓冲
// glut与交互相关变量
int windowWidth = 512; // 窗口宽
int windowHeight = 512; // 窗口高
bool keyboardState[1024]; // 键盘状态数组 keyboardState[x]==true 表示按下x键
// 延迟渲染阶段
GLuint gbufferProgram;
GLuint gbufferFBO; // gbuffer 阶段帧缓冲
GLuint gcolor; // 基本颜色纹理
GLuint gdepth; // 深度纹理
GLuint gworldpos; // 世界坐标纹理
GLuint gnormal; // 法线纹理
// 后处理阶段
GLuint composite0;
// --------------- end of global variable definition --------------- //
// 读取文件并且返回一个长字符串表示文件内容
std::string readShaderFile(std::string filepath)
{
std::string res, line;
std::ifstream fin(filepath);
if (!fin.is_open())
{
std::cout << "文件 " << filepath << " 打开失败" << std::endl;
exit(-1);
}
while (std::getline(fin, line))
{
res += line + '\n';
}
fin.close();
return res;
}
// 获取着色器对象
GLuint getShaderProgram(std::string fshader, std::string vshader)
{
// 读取shader源文件
std::string vSource = readShaderFile(vshader);
std::string fSource = readShaderFile(fshader);
const char* vpointer = vSource.c_str();
const char* fpointer = fSource.c_str();
// 容错
GLint success;
GLchar infoLog[512];
// 创建并编译顶点着色器
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, (const GLchar**)(&vpointer), NULL);
glCompileShader(vertexShader);
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success); // 错误检测
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
std::cout << "顶点着色器 " + vshader + " 编译错误\n" << infoLog << std::endl;
exit(-1);
}
// 创建并且编译片段着色器
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, (const GLchar**)(&fpointer), NULL);
glCompileShader(fragmentShader);
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success); // 错误检测
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << "片段着色器 " + fshader + " 编译错误\n" << infoLog << std::endl;
exit(-1);
}
// 链接两个着色器到program对象
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
// 删除着色器对象
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
return shaderProgram;
}
// 鼠标滚轮函数
void mouseWheel(int wheel, int direction, int x, int y)
{
// zFar += 1 * direction * 0.1;
glutPostRedisplay(); // 重绘
}
// 鼠标运动函数
void mouse(int x, int y)
{
// 调整旋转
camera.yaw += 35 * (x - float(windowWidth) / 2.0) / windowWidth;
camera.yaw = glm::mod(camera.yaw + 180.0f, 360.0f) - 180.0f; // 取模范围 -180 ~ 180
camera.pitch += -35 * (y - float(windowHeight) / 2.0) / windowHeight;
camera.pitch = glm::clamp(camera.pitch, -89.0f, 89.0f);
glutWarpPointer(windowWidth / 2.0, windowHeight / 2.0);
glutPostRedisplay(); // 重绘
}
// 键盘回调函数
void keyboardDown(unsigned char key, int x, int y)
{
keyboardState[key] = true;
}
void keyboardDownSpecial(int key, int x, int y)
{
keyboardState[key] = true;
}
void keyboardUp(unsigned char key, int x, int y)
{
keyboardState[key] = false;
}
void keyboardUpSpecial(int key, int x, int y)
{
keyboardState[key] = false;
}
// 根据键盘状态判断移动
void move()
{
float cameraSpeed = 0.035f;
// 相机控制
if (keyboardState['w']) camera.position += cameraSpeed * camera.direction;
if (keyboardState['s']) camera.position -= cameraSpeed * camera.direction;
if (keyboardState['a']) camera.position -= cameraSpeed * glm::normalize(glm::cross(camera.direction, camera.up));
if (keyboardState['d']) camera.position += cameraSpeed * glm::normalize(glm::cross(camera.direction, camera.up));
if (keyboardState[GLUT_KEY_CTRL_L]) camera.position.y -= cameraSpeed;
if (keyboardState[' ']) camera.position.y += cameraSpeed;
// 光源位置控制
if (keyboardState['i']) shadowCamera.position.x += cameraSpeed;
if (keyboardState['I']) shadowCamera.position.x -= cameraSpeed;
if (keyboardState['o']) shadowCamera.position.y += cameraSpeed;
if (keyboardState['O']) shadowCamera.position.y -= cameraSpeed;
glutPostRedisplay(); // 重绘
}
GLuint loadCubemap(std::vector<const GLchar*> faces)
{
GLuint textureID;
glGenTextures(1, &textureID);
glActiveTexture(GL_TEXTURE0);
int width, height;
unsigned char* image;
glBindTexture(GL_TEXTURE_CUBE_MAP, textureID);
for (GLuint i = 0; i < faces.size(); i++)
{
image = SOIL_load_image(faces[i], &width, &height, 0, SOIL_LOAD_RGB);
glTexImage2D(
GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0,
GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image
);
}
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
return textureID;
}
// 初始化
void init()
{
// 生成着色器程序对象
gbufferProgram = getShaderProgram("shaders/gbuffer.fsh", "shaders/gbuffer.vsh");
shadowProgram = getShaderProgram("shaders/shadow.fsh", "shaders/shadow.vsh");
debugProgram = getShaderProgram("shaders/debug.fsh", "shaders/debug.vsh");
skyboxProgram = getShaderProgram("shaders/skybox.fsh", "shaders/skybox.vsh");
composite0 = getShaderProgram("shaders/composite0.fsh", "shaders/composite0.vsh");
// ------------------------------------------------------------------------ //
// 读取 obj 模型
Model tree1 = Model();
tree1.translate = glm::vec3(2.5, 0, 2);
tree1.scale = glm::vec3(0.0025, 0.0025, 0.0025);
tree1.load("models/tree/tree02.obj");
models.push_back(tree1);
Model tree2 = Model();
tree2.translate = glm::vec3(10, 0, 7);
tree2.scale = glm::vec3(0.0015, 0.0015, 0.0015);
tree2.load("models/tree/tree02.obj");
models.push_back(tree2);
Model plane = Model();
plane.translate = glm::vec3(0, -1.1, 0);
plane.scale = glm::vec3(10, 10, 10);
plane.rotate = glm::vec3(0, 0, 0);
plane.load("models/plane/plane.obj");
models.push_back(plane);
// 光源位置标志物
Model vlight = Model();
vlight.translate = glm::vec3(1, 0, -1);
vlight.rotate = glm::vec3(-90, 0, 0);
vlight.scale = glm::vec3(0.03, 0.03, 0.03);
vlight.load("models/duck/12248_Bird_v1_L2.obj");
models.push_back(vlight);
// ------------------------------------------------------------------------ //
// 生成一个四方形做荧幕 -- 用以显示纹理中的数据
Mesh msquare;
msquare.vertexPosition = {
glm::vec3(-1, -1, 0), glm::vec3(1, -1, 0), glm::vec3(-1, 1, 0), glm::vec3(1, 1, 0) };
msquare.vertexTexcoord = {
glm::vec2(0, 0), glm::vec2(1, 0), glm::vec2(0, 1), glm::vec2(1, 1) };
msquare.index = {
0,1,2,2,1,3 };
msquare.bindData();
screen.meshes.push_back(msquare);
// ------------------------------------------------------------------------ //
// 生成一个立方体做天空盒的 “画布”
Mesh cube;
cube.vertexPosition = {
// 立方体的 8 个顶点
glm::vec3(-1, -1, -1),glm::vec3(1, -1, -1),glm::vec3(-1, 1, -1),glm::vec3(1, 1, -1),
glm::vec3(-1, -1, 1),glm::vec3(1, -1, 1),glm::vec3(-1, 1, 1),glm::vec3(1, 1, 1)
};
cube.index = {
0,3,1,0,2,3,1,5,4,1,4,0,4,2,0,4,6,2,5,6,4,5,7,6,2,6,7,2,7,3,1,7,5,1,3,7 };
cube.bindData();
skybox.meshes.push_back(cube);
// 加载立方体贴图
std::vector<const GLchar*> faces;
faces.push_back("skybox/right.jpg");
faces.push_back("skybox/left.jpg");
faces.push_back("skybox/top.jpg");
faces.push_back("skybox/bottom.jpg");
faces.push_back("skybox/back.jpg");
faces.push_back("skybox/front.jpg");
/*
faces.push_back("skybox/DOOM16RT.png");
faces.push_back("skybox/DOOM16LF.png");
faces.push_back("skybox/DOOM16UP.png");
faces.push_back("skybox/DOOM16DN.png");
faces.push_back("skybox/DOOM16FT.png");
faces.push_back("skybox/DOOM16BK.png");
*/
skyboxTexture = loadCubemap(faces);
// ------------------------------------------------------------------------ //
// 正交投影参数配置 -- 视界体范围 -- 调整到场景一般大小即可
shadowCamera.left = -30;
shadowCamera.right = 30;
shadowCamera.bottom = -30;
shadowCamera.top = 30;
shadowCamera.position = glm::vec3(0, 4, 15);
// 创建shadow帧缓冲
glGenFramebuffers(1, &shadowMapFBO);
// 创建阴影纹理
glGenTextures(1, &shadowTexture);
glBindTexture(GL_TEXTURE_2D, shadowTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, shadowMapResolution, shadowMapResolution, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将阴影纹理绑定到 shadowMapFBO 帧缓冲
glBindFramebuffer(GL_FRAMEBUFFER, shadowMapFBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, shadowTexture, 0);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// ------------------------------------------------------------------------ //
// 创建 gubffer 帧缓冲
glGenFramebuffers(1, &gbufferFBO);
glBindFramebuffer(GL_FRAMEBUFFER, gbufferFBO);
// 创建颜色纹理
glGenTextures(1, &gcolor);
glBindTexture(GL_TEXTURE_2D, gcolor);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, windowWidth, windowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将颜色纹理绑定到 0 号颜色附件
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, gcolor, 0);
// 创建法线纹理
glGenTextures(1, &gnormal);
glBindTexture(GL_TEXTURE_2D, gnormal);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, windowWidth, windowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将法线纹理绑定到 1 号颜色附件
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, gnormal, 0);
// 创建世界坐标纹理
glGenTextures(1, &gworldpos);
glBindTexture(GL_TEXTURE_2D, gworldpos);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, windowWidth, windowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将世界坐标纹理绑定到 2 号颜色附件
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, GL_TEXTURE_2D, gworldpos, 0);
// 创建深度纹理
glGenTextures(1, &gdepth);
glBindTexture(GL_TEXTURE_2D, gdepth);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, windowWidth, windowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// 将深度纹理绑定到深度附件
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, gdepth, 0);
// 指定附件索引
GLuint attachments[3] = {
GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2 };
glDrawBuffers(3, attachments);
glBindFramebuffer(GL_FRAMEBUFFER, 0); // 解绑
// ------------------------------------------------------------------------ //
glEnable(GL_DEPTH_TEST); // 开启深度测试
glClearColor(1.0, 1.0, 1.0, 1.0); // 背景颜色
}
// 显示回调函数
void display()
{
move(); // 移动控制 -- 控制相机位置
// 最后一个物体作为光源位置的标志物
models.back().translate = shadowCamera.position + glm::vec3(0, 0, 2);
// ------------------------------------------------------------------------ //
// 从光源方向进行渲染
glUseProgram(shadowProgram);
glBindFramebuffer(GL_FRAMEBUFFER, shadowMapFBO);
glClear(GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, shadowMapResolution, shadowMapResolution);
// 光源看向世界坐标原点
shadowCamera.direction = glm::normalize(glm::vec3(0, 0, 0) - shadowCamera.position);
// 传视图矩阵
glUniformMatrix4fv(glGetUniformLocation(shadowProgram, "view"), 1, GL_FALSE, glm::value_ptr(shadowCamera.getViewMatrix(false)));
// 传投影矩阵
glUniformMatrix4fv(glGetUniformLocation(shadowProgram, "projection"), 1, GL_FALSE, glm::value_ptr(shadowCamera.getProjectionMatrix(false)));
// 从光源方向进行绘制
for (auto m : models)
{
m.draw(shadowProgram);
}
// ------------------------------------------------------------------------ //
// 绘制天空盒 -- 输出到 gbuffer 阶段的 3 张纹理中
glUseProgram(skyboxProgram);
glBindFramebuffer(GL_FRAMEBUFFER, gbufferFBO);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, windowWidth, windowHeight);
// 传视图,投影矩阵
glUniformMatrix4fv(glGetUniformLocation(skyboxProgram, "view"), 1, GL_FALSE, glm::value_ptr(camera.getViewMatrix()));
glUniformMatrix4fv(glGetUniformLocation(skyboxProgram, "projection"), 1, GL_FALSE, glm::value_ptr(camera.getProjectionMatrix()));
// 传cubemap纹理
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_CUBE_MAP, skyboxTexture);
glUniform1i(glGetUniformLocation(skyboxProgram, "skybox"), 1);
// 传递 zfar 和 znear 方便让天空盒的坐标置于最大视距
glUniform1f(glGetUniformLocation(skyboxProgram, "near"), camera.zNear);
glUniform1f(glGetUniformLocation(skyboxProgram, "far"), camera.zFar);
// 立方体永远跟随相机
skybox.translate = camera.position;
glDepthMask(GL_FALSE);
skybox.draw(skyboxProgram);
glDepthMask(GL_TRUE);
// ------------------------------------------------------------------------ //
// 正常绘制 -- 输出到 gbuffer 阶段的 3 张纹理中
glUseProgram(gbufferProgram);
// 传视图矩阵
glUniformMatrix4fv(glGetUniformLocation(gbufferProgram, "view"), 1, GL_FALSE, glm::value_ptr(camera.getViewMatrix()));
// 传投影矩阵
glUniformMatrix4fv(glGetUniformLocation(gbufferProgram, "projection"), 1, GL_FALSE, glm::value_ptr(camera.getProjectionMatrix()));
// 正常绘制
for (auto m : models)
{
m.draw(gbufferProgram);
}
// ------------------------------------------------------------------------ //
// 后处理阶段: composite0 着色器进行渲染
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glDisable(GL_DEPTH_TEST);
glUseProgram(composite0);
glViewport(0, 0, windowWidth, windowHeight);
// 传递 zfar 和 znear 方便转线性深度
glUniform1f(glGetUniformLocation(composite0, "near"), camera.zNear);
glUniform1f(glGetUniformLocation(composite0, "far"), camera.zFar);
// 传 gcolor 纹理
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, gcolor);
glUniform1i(glGetUniformLocation(composite0, "gcolor"), 1);
// 传 gnormal 纹理
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, gnormal);
glUniform1i(glGetUniformLocation(composite0, "gnormal"), 2);
// 传 gworldpos 纹理
glActiveTexture(GL_TEXTURE3);
glBindTexture(GL_TEXTURE_2D, gworldpos);
glUniform1i(glGetUniformLocation(composite0, "gworldpos"), 3);
// 传 gdepth 纹理
glActiveTexture(GL_TEXTURE4);
glBindTexture(GL_TEXTURE_2D, gdepth);
glUniform1i(glGetUniformLocation(composite0, "gdepth"), 4);
// 传阴影深度纹理
glActiveTexture(GL_TEXTURE5);
glBindTexture(GL_TEXTURE_2D, shadowTexture);
glUniform1i(glGetUniformLocation(composite0, "shadowtex"), 5);
// 传递矩阵: 转换到光源坐标的变换矩阵
glm::mat4 shadowVP = shadowCamera.getProjectionMatrix(false) * shadowCamera.getViewMatrix(false);
glUniformMatrix4fv(glGetUniformLocation(composite0, "shadowVP"), 1, GL_FALSE, glm::value_ptr(shadowVP));
// 传递光源位置
glUniform3fv(glGetUniformLocation(composite0, "lightPos"), 1, glm::value_ptr(shadowCamera.position));
// 传递相机位置
glUniform3fv(glGetUniformLocation(composite0, "cameraPos"), 1, glm::value_ptr(camera.position));
// 绘制
screen.draw(composite0);
glEnable(GL_DEPTH_TEST);
// ------------------------------------------------------------------------ //
/*
// debug着色器输出一个四方形以显示纹理中的数据
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glDisable(GL_DEPTH_TEST); // 需要取消深度测试以保证其覆盖在原画面上
glUseProgram(debugProgram);
glViewport(0, 0, windowWidth, windowHeight);
// 传递 zfar 和 znear 方便转线性深度
glUniform1f(glGetUniformLocation(debugProgram, "near"), camera.zNear);
glUniform1f(glGetUniformLocation(debugProgram, "far"), camera.zFar);
// 传 gcolor 纹理
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, gcolor);
glUniform1i(glGetUniformLocation(debugProgram, "gcolor"), 1);
// 传 gnormal 纹理
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, gnormal);
glUniform1i(glGetUniformLocation(debugProgram, "gnormal"), 2);
// 传 gworldpos 纹理
glActiveTexture(GL_TEXTURE3);
glBindTexture(GL_TEXTURE_2D, gworldpos);
glUniform1i(glGetUniformLocation(debugProgram, "gworldpos"), 3);
// 传 gdepth 纹理
glActiveTexture(GL_TEXTURE4);
glBindTexture(GL_TEXTURE_2D, gdepth);
glUniform1i(glGetUniformLocation(debugProgram, "gdepth"), 4);
// 传阴影深度纹理
glActiveTexture(GL_TEXTURE5);
glBindTexture(GL_TEXTURE_2D, shadowTexture);
glUniform1i(glGetUniformLocation(debugProgram, "shadowtex"), 5);
// 绘制
screen.draw(debugProgram);
glEnable(GL_DEPTH_TEST);
*/
// ------------------------------------------------------------------------ //
glutSwapBuffers(); // 交换缓冲区
}
// -------------------------------- main -------------------------------- //
int main(int argc, char** argv)
{
glutInit(&argc, argv); // glut初始化
glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH);
glutInitWindowSize(windowWidth, windowHeight);// 窗口大小
glutCreateWindow("10 - deferred render"); // 创建OpenGL上下文
#ifdef __APPLE__
#else
glewInit();
#endif
init();
// 绑定鼠标移动函数 --
//glutMotionFunc(mouse); // 左键按下并且移动
glutPassiveMotionFunc(mouse); // 鼠标直接移动
//glutMouseWheelFunc(mouseWheel); // 滚轮缩放
// 绑定键盘函数
glutKeyboardFunc(keyboardDown);
glutSpecialFunc(keyboardDownSpecial);
glutKeyboardUpFunc(keyboardUp);
glutSpecialUpFunc(keyboardUpSpecial);
glutDisplayFunc(display); // 设置显示回调函数 -- 每帧执行
glutMainLoop(); // 进入主循环
return 0;
}