顶点着色器代码
#version 300 es
layout(location = 0) in vec3 position; //顶点
layout(location = 1) in vec3 normal; //法向量
layout(location = 2) in vec2 texCoord; //纹理坐标
uniform mat4 view;
uniform mat4 projection;
out vec3 outNormal; //法向量
out vec3 FragPo; //顶点在世界坐标位置
out vec2 outTexCoord;//纹理坐标
void main()
{
FragPo = position;
outNormal = normal;
outTexCoord = texCoord;
gl_Position = projection * view * vec4(position,1.0);
}
片元着色器代码
#version 300 es
precision mediump float;
out vec4 FragColor;
uniform vec3 lightColor; //光源颜色
uniform vec3 lightPo; //光源位置
uniform vec3 viewPo; //视角位置
uniform sampler2D Texture; //物体纹理
uniform sampler2D specularTexture; //镜面纹理
in vec2 outTexCoord; //纹理坐标
in vec3 outNormal; //顶点法向量
in vec3 FragPo; //顶点坐标
点光源版本
void pointLight(){
float ambientStrength = 0.3; //环境因子
float specularStrength = 2.0; //镜面强度
float reflectance = 256.0; //反射率
float constantPara = 1.0f; //距离衰减常量
float linearPara = 0.09f; //线性衰减常量
float quadraticPara = 0.032f; //二次衰减常量
//环境光 = 环境因子 * 物体的材质颜色
vec3 ambient = ambientStrength * texture(Texture,outTexCoord).rgb;
//漫反射
vec3 norm = normalize(outNormal);
//当前顶点 至 光源的的单位向量
vec3 lightDir = normalize(lightPo - FragPo);
//DiffuseFactor=光源与法线夹角 max(0,dot(N,L))
float diff = max(dot(norm,lightDir),0.0);
//漫反射光颜色计算 = 光源的漫反射颜色 * 物体的漫发射材质颜色 * DiffuseFactor
vec3 diffuse = diff * lightColor*texture(Texture,outTexCoord).rgb;
//镜面反射
vec3 viewDir = normalize(viewPo - FragPo);
// reflect (genType I, genType N),返回反射向量
vec3 reflectDir = reflect(-lightDir,outNormal);
//SpecularFactor = power(max(0,dot(N,H)),shininess)
float spec = pow(max(dot(viewDir, reflectDir),0.0),reflectance);
//镜面反射颜色 = 光源的镜面光的颜色 * 物体的镜面材质颜色 * SpecularFactor
vec3 specular = specularStrength * spec * texture(specularTexture,outTexCoord).rgb;
//衰减因子计算
float LFDistance = length(lightPo - FragPo);
//衰减因子 = 1.0/(距离衰减常量 + 线性衰减常量 * 距离 + 二次衰减常量 * 距离的平方)
float lightWeakPara = 1.0/(constantPara + linearPara * LFDistance + quadraticPara * (LFDistance*LFDistance));
//光照颜色 =(环境颜色 + 漫反射颜色 + 镜面反射颜色)* 衰减因子
vec3 res = (ambient + diffuse + specular)*lightWeakPara;
//最终输出的颜色
FragColor = vec4(res,1.0);
}
平行光版本
void parallelLight(){
float ambientStrength = 0.3; //环境因子
float specularStrength = 2.0; //镜面强度
float reflectance = 256.0; //反射率
//平行光方向
vec3 paraLightDir = normalize(vec3(-0.2,-1.0,-0.3));
//环境光 = 环境因子 * 物体的材质颜色
vec3 ambient = ambientStrength * texture(Texture,outTexCoord).rgb;
//漫反射
vec3 norm = normalize(outNormal);
//当前顶点至光源的的单位向量
vec3 lightDir = normalize(lightPo - FragPo);
//DiffuseFactor=光源与paraLightDir 平行光夹角 max(0,dot(N,L))
float diff = max(dot(norm,paraLightDir),0.0);
//漫反射光颜色计算 = 光源的漫反射颜色 * 物体的漫发射材质颜色 * DiffuseFactor
vec3 diffuse = diff * lightColor * texture(Texture,outTexCoord).rgb;
//镜面反射
vec3 viewDir = normalize(viewPo - FragPo);
// reflect (genType I, genType N),返回反射向量 -paraLightDir平行光
vec3 reflectDir = reflect(-paraLightDir,outNormal);
//SpecularFactor = power(max(0,dot(N,H)),shininess)
float spec = pow(max(dot(viewDir, reflectDir),0.0),reflectance);
//镜面反射颜色 = 光源的镜面光的颜色 * 物体的镜面材质颜色 * SpecularFactor
vec3 specular = specularStrength * spec * texture(specularTexture,outTexCoord).rgb;
//距离衰减常量
float constantPara = 1.0f;
//线性衰减常量
float linearPara = 0.09f;
//二次衰减常量
float quadraticPara = 0.032f;
//衰减因子计算
float LFDistance = length(lightPo - FragPo);
//衰减因子 = 1.0/(距离衰减常量 + 线性衰减常量 * 距离 + 二次衰减常量 * 距离的平方)
float lightWeakPara = 1.0/(constantPara + linearPara * LFDistance + quadraticPara * (LFDistance*LFDistance));
//光照颜色 =(环境颜色 + 漫反射颜色 + 镜面反射颜色)* 衰减因子
vec3 res = (ambient + diffuse + specular)*lightWeakPara;
//最终输出的颜色
FragColor = vec4(res,1.0);
}
聚光版本
void Spotlight(){
float ambientStrength = 0.3; //环境因子
float specularStrength = 2.0; //镜面强度
float reflectance = 256.0; //反射率
//环境光 = 环境因子 * 物体的材质颜色
vec3 ambient = ambientStrength * texture(Texture,outTexCoord).rgb;
//漫反射
vec3 norm = normalize(outNormal);
vec3 lightDir = normalize(lightPo - FragPo); //当前顶点 至 光源的的单位向量
//DiffuseFactor=光源与paraLightDir lightDir夹角 max(0,dot(N,L))
float diff = max(dot(norm,lightDir),0.0); //光源与法线夹角
//漫反射光颜色计算 = 光源的漫反射颜色 * 物体的漫发射材质颜色 * DiffuseFactor
vec3 diffuse = diff * lightColor*texture(Texture,outTexCoord).rgb;
//镜面反射
vec3 viewDir = normalize(viewPo - FragPo);
// reflect (genType I, genType N),返回反射向量
vec3 reflectDir = reflect(-lightDir,outNormal);
//SpecularFactor = power(max(0,dot(N,H)),shininess)
float spec = pow(max(dot(viewDir, reflectDir),0.0),reflectance);
//镜面反射颜色 = 光源的镜面光的颜色 * 物体的镜面材质颜色 * SpecularFactor
vec3 specular = specularStrength * spec * texture(specularTexture,outTexCoord).rgb;
float constantPara = 1.0f; //距离衰减常量
float linearPara = 0.09f; //线性衰减常量
float quadraticPara = 0.032f; //二次衰减常量
//衰减因子计算
float LFDistance = length(lightPo - FragPo);
//衰减因子 = 1.0/(距离衰减常量 + 线性衰减常量 * 距离 + 二次衰减常量 * 距离的平方)
float lightWeakPara = 1.0/(constantPara + linearPara * LFDistance + quadraticPara * (LFDistance*LFDistance));
//聚光灯切角 (一些复杂的计算操作 应该让CPU做,提高效率,不变的量也建议外部传输,避免重复计算)
float inCutOff = cos(radians(10.0f));
float outCutOff = cos(radians(15.0f));
vec3 spotDir = vec3(-1.2f,-1.0f,-2.0f);
//聚光灯因子 = clamp((外环的聚光灯角度cos值 - 当前顶点的聚光灯角度cos值)/(外环的聚光灯角度cos值- 内环聚光灯的角度的cos值),0,1)；
float theta = dot(lightDir,normalize(-spotDir));
//(外环的聚光灯角度cos值- 内环聚光灯的角度的cos值)
float epsilon = inCutOff - outCutOff;
//(外环的聚光灯角度cos值 - 当前顶点的聚光灯角度cos值) / (外环的聚光灯角度cos值- 内环聚光灯的角度的cos值)
float intensity = clamp((theta - outCutOff)/epsilon,0.0,1.0);
vec3 res = (ambient + diffuse + specular)*intensity*lightWeakPara;
FragColor = vec4(res,1.0);
}
GLKit层部分核心代码
设置VBO
// 顶点坐标/法线坐标/纹理坐标
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glEnableVertexAttribArray(2);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void*)NULL);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void*)(3*sizeof(float)));
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void*)(6*sizeof(float)));
渲染
glEnable(GL_DEPTH_TEST);
glClearColor(1.0, 0.0, 0.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, self.frame.size.width, self.frame.size.height);
//光照颜色->片元/顶点着色器
glUniform3f(glGetUniformLocation(program, "lightColor"), 1.0f, 1.0f, 1.0f);
//投影矩阵->顶点着色器
float aspect = (float)self.bounds.size.width / (float)self.bounds.size.height;
GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathRadiansToDegrees(45.0f), aspect, 0.1f, 800.0f) ;
glUniformMatrix4fv(glGetUniformLocation(program, "projection"), 1, GL_FALSE, (GLfloat*)projectionMatrix.m);
//模型视图矩阵-->顶点着色器
float radius = 10.0f;
float camX = sin(CACurrentMediaTime()) * radius;
float camZ = cos(CACurrentMediaTime()) * radius;
GLKVector3 viewPo = {camX,camX,camZ};
//获取世界坐标系去模型矩阵中.
/*
LKMatrix4 GLKMatrix4MakeLookAt(float eyeX, float eyeY, float eyeZ,
float centerX, float centerY, float centerZ,
float upX, float upY, float upZ)
等价于 OpenGL 中
void gluLookAt(GLdouble eyex,GLdouble eyey,GLdouble eyez,GLdouble centerx,GLdouble centery,GLdouble centerz,GLdouble upx,GLdouble upy,GLdouble upz);
目的:根据你的设置返回一个4x4矩阵变换的世界坐标系坐标。
参数1:眼睛位置的x坐标
参数2:眼睛位置的y坐标
参数3:眼睛位置的z坐标
第一组:就是脑袋的位置
参数4:正在观察的点的X坐标
参数5:正在观察的点的Y坐标
参数6:正在观察的点的Z坐标
第二组:就是眼睛所看物体的位置
参数7:摄像机上向量的x坐标
参数8:摄像机上向量的y坐标
参数9:摄像机上向量的z坐标
第三组:就是头顶朝向的方向(因为你可以头歪着的状态看物体)
*/
GLKMatrix4 view1 = GLKMatrix4MakeLookAt(camX,camX,camZ,0,0,0,0,1,0);
view1 = GLKMatrix4Scale(view1, 5.0f, 5.0f, 5.0f);
glUniformMatrix4fv(glGetUniformLocation(program, "view"), 1, GL_FALSE, (GLfloat *)view1.m);
//光源位置
glUniform3f(glGetUniformLocation(program, "lightPo"), lightPo.x, lightPo.y, lightPo.z);
//观察者位置
glUniform3f(glGetUniformLocation(program, "viewPo"), viewPo.x, viewPo.y, viewPo.z);
glDrawArrays(GL_TRIANGLES, 0, 36);
[context presentRenderbuffer:GL_RENDERBUFFER];
