按照 learnopengl 教程 ( https://learnopengl.com/Advanced-Lighting/Deferred-Shading )，作者保留了 GLSL 所示的固定光量（32 盏灯）：
#version 330 core
out vec4 FragColor;
in vec2 TexCoords;
uniform sampler2D gPosition;
uniform sampler2D gNormal;
uniform sampler2D gAlbedoSpec;
struct Light {
vec3 Position;
color;
};
const int NR_LIGHTS = 32;
uniform Light lights [NR_LIGHTS];
uniform vec3 viewPos;
void main ()
{
// retrieve data from G-buffer
vec3 FragPos = texture (gPosition, TexCoords) .rgb;
vec3 Normal = texture (gNormal, TexCoords) .rgb;
vec3 Albedo = texture (gAlbedoSpec, TexCoords) .rgb;
float Specular = texture (gAlbedoSpec, TexCoords) .a;
// then calculate lighting as usual
vec3 lighting = Albedo * 0.1; // hard-coded ambient component
vec3 viewDir = normalize (viewPos - FragPos);
for (int i = 0; i <NR_LIGHTS; ++ i)
{
// diffuse
vec3 lightDir = normalize (lights [i] .Position - FragPos);
vec3 diffuse = max (dot (Normal, lightDir), 0.0) * Albedo * lights [i] .Color;
lighting + = diffuse;
}
FragColor = vec4 (lighting, 1.0);
}
在应用灯光时：
glBindFramebuffer (GL_FRAMEBUFFER, 0);
// 2. lighting pass: calculate lighting by iterating over screen filled quad pixel-by-pixel using the gbuffer's content.
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
shaderLightingPass.use ();
glActiveTexture (GL_TEXTURE0);
glBindTexture (GL_TEXTURE_2D, gPosition);
glActiveTexture (GL_TEXTURE1);
glBindTexture (GL_TEXTURE_2D, gNormal);
glActiveTexture (GL_TEXTURE2);
glBindTexture (GL_TEXTURE_2D, gAlbedoSpec);
// send light relevant uniforms
for (unsigned int i = 0; i <lightPositions.size (); i ++)
{
shaderLightingPass.setVec3 ("lights [" + std :: to_string (i) + "] .Position", lightPositions [i]);
shaderLightingPass.setVec3 ("lights [" + std :: to_string (i) + "] .Color", lightColors [i]);
// update attenuation parameters and calculate radius
const float constant = 1.0; // note that we do not send this to the shader, we assume it is always 1.0 (in our case)
const float linear = 0.7;
const float quadratic = 1.8;
shaderLightingPass.setFloat ("lights [" + std :: to_string (i) + "] .Linear", linear);
shaderLightingPass.setFloat ("lights [" + std :: to_string (i) + "] .Quadratic", quadratic);
}
shaderLightingPass.setVec3 ("viewPos", camera.Position);
// finally render quad
renderQuad ();
但我希望能够添加尽可能多的灯光，因为我的项目将有无数灯光（激光枪、篝火、爆炸），所以我做了一些更改：
GLSL：
uniform Light light;
uniform vec3 viewPos;
void main()
{
// retrieve data from gbuffer
vec3 FragPos = texture(gPosition, TexCoords).rgb;
vec3 Normal = texture(gNormal, TexCoords).rgb;
vec3 Diffuse = texture(gAlbedoSpec, TexCoords).rgb;
float Specular = texture(gAlbedoSpec, TexCoords).a;
// then calculate lighting as usual
vec3 lighting = Diffuse * 0.1; // hard-coded ambient component
vec3 viewDir = normalize(viewPos - FragPos);
// diffuse
vec3 lightDir = normalize(light.Position - FragPos);
vec3 diffuse = max(dot(Normal, lightDir), 0.0) * Diffuse * light.Color;
// specular
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(Normal, halfwayDir), 0.0), 16.0);
vec3 specular = light.Color * spec * Specular;
// attenuation
float distance = length(light.Position - FragPos);
float attenuation = 1.0 / (1.0 + light.Linear * distance + light.Quadratic * distance * distance);
diffuse *= attenuation;
specular *= attenuation;
lighting += diffuse + specular;
FragColor = vec4(lighting, 1.0);
}
然后我一个一个地传递值并渲染一个四边形：
for (unsigned int i = 0; i < lightPositions.size(); i++)
{
shaderLightingPass.use();
shaderLightingPass.setInt("gPosition", 0);
shaderLightingPass.setInt("gNormal", 1);
shaderLightingPass.setInt("gAlbedoSpec", 2);
shaderLightingPass.setVec3("light.Position", lightPositions[i]);
shaderLightingPass.setVec3("light.Color", lightColors[i]);
const float constant = 1.0; // note that we don't send this to the shader, we assume it is always 1.0 (in our case)
const float linear = 0.7;
const float quadratic = 0.08;
shaderLightingPass.setFloat("light.Linear", linear);
shaderLightingPass.setFloat("light.Quadratic", quadratic);
shaderLightingPass.setVec3("viewPos", camera.Position);
renderQuad();
glUseProgram(-1);
}
并且还添加了一个新的着色器来在屏幕上渲染帧缓冲区：
screenShader.use();
renderQuad();
但我的代码只呈现第一盏灯： 结果 谁能告诉我我做错了什么以及如何在最终结果中添加灯光？
