Java 添加灯光时,环境光变得更亮(OpenGL,法线贴图)
在过去的几天里,我在Java中玩了lightning(Libgdx)。我是OpenGL或着色器的新手,我偶然发现了一个很好的教程,介绍了如何使用法线贴图实现照明()。到目前为止,我设法做到这一点与一个灯光,现在我正试图做同样的效果与多个灯光。我尝试使用添加混合为每个灯光执行一次绘制调用。阴影绘制正确,但每次添加灯光时,环境光颜色都会变得更亮。我试了几次,但都没用,我被卡住了 我的渲染方法:Java 添加灯光时,环境光变得更亮(OpenGL,法线贴图),java,opengl,libgdx,shader,blending,Java,Opengl,Libgdx,Shader,Blending,在过去的几天里,我在Java中玩了lightning(Libgdx)。我是OpenGL或着色器的新手,我偶然发现了一个很好的教程,介绍了如何使用法线贴图实现照明()。到目前为止,我设法做到这一点与一个灯光,现在我正试图做同样的效果与多个灯光。我尝试使用添加混合为每个灯光执行一次绘制调用。阴影绘制正确,但每次添加灯光时,环境光颜色都会变得更亮。我试了几次,但都没用,我被卡住了 我的渲染方法: @Override public void render () { renderToFbo(Gdx
@Override
public void render () {
renderToFbo(Gdx.input.getX(), Gdx.graphics.getHeight() - Gdx.input.getY());
renderToScreen(Gdx.input.getX(), Gdx.graphics.getHeight() - Gdx.input.getY());
renderToFbo(200, 200);
batch.setBlendFunction(GL_ONE,GL_ONE_MINUS_SRC_COLOR);
renderToScreen(200,200);
renderToFbo(500, 500);
batch.setBlendFunction(GL_ONE, GL_ONE_MINUS_SRC_COLOR);
renderToScreen(500,500);
}
private void renderToFbo(float posX, float posY){
fbo.begin();
batch.setBlendFunction(GL_ONE, GL_ZERO);
batch.setShader(defaultShader);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.begin();
batch.draw(lightMap, posX - lightSize / 2, posY - lightSize / 2, lightSize,lightSize);
batch.end();
fbo.end();
}
private void renderToScreen(float posX, float posY){
batch.setShader(lightningShader);
batch.begin();
float x = posX / (float) Gdx.graphics.getWidth();
float y = posY / (float) Gdx.graphics.getHeight();
LIGHT_POS.x = x;
LIGHT_POS.y = y;
lightningShader.setUniformf("lightPos", LIGHT_POS.x, LIGHT_POS.y, LIGHT_POS.z);
fbo.getColorBufferTexture().bind(2);
normalMap.bind(1);
texture.bind(0);
batch.draw(texture, 0,0);
batch.end();
}
这里是我的片段着色器:
varying vec4 vColor;
varying vec2 vTexCoord;
uniform sampler2D u_texture; //diffuse map
uniform sampler2D u_normals; //normal map
uniform sampler2D u_light; //light map
uniform vec2 resolution; //resolution of screen
uniform vec3 lightPos; //light position, normalized
uniform vec4 lightColor; //light RGBA -- alpha is intensity
uniform vec4 ambientColor; //ambient RGBA -- alpha is intensity
void main() {
//RGBA of our diffuse color
vec4 diffuseColor = texture2D(u_texture, vTexCoord);
//RGB of our normal map
vec3 normalMap = texture2D(u_normals, vTexCoord).rgb;
//NormalMap.g = 1.0 - NormalMap.g;
//The delta position of light
vec3 lightDir = vec3(lightPos.xy - (gl_FragCoord.xy / resolution.xy), lightPos.z);
lightDir.x *= resolution.x / resolution.y;
//normalize our vectors
vec3 N = normalize(normalMap * 2.0 - 1.0);
vec3 L = normalize(lightDir);
//Pre-multiply light color with intensity
//Then perform "N dot L" to determine our diffuse term
vec3 diffuse = (lightColor.rgb * lightColor.a) * max(dot(N, L), 0.0);
//pre-multiply ambient color with intensity
vec3 ambient = ambientColor.rgb * ambientColor.a;
//calculate attenuation from lightmap
vec2 lighCoord = (gl_FragCoord.xy / resolution.xy);
vec3 attenuation = texture2D(u_light, lighCoord).rgb;
//the calculation which brings it all together
vec3 intensity = ambient + diffuse * attenuation;
vec3 finalColor = diffuseColor.rgb * intensity;
gl_FragColor = vColor * vec4(finalColor, diffuseColor.a);
}
要使用单个渲染调用执行此操作,片段着色器必须接受要处理的灯光位置数组。着色器必须在编译时知道数组大小,因此应将数组设置为足够大,以容纳所需数量的灯光(当需要较少的灯光时,可以将其余灯光设置为黑色) 我在下面修改了你的着色器,只是假设它在你的代码中正确工作。我不知道你在用光照贴图做什么,所以我用更传统的东西代替了你的衰减计算
varying vec4 vColor;
varying vec2 vTexCoord;
uniform sampler2D u_texture; //diffuse map
uniform sampler2D u_normals; //normal map
const int LIGHT_COUNT = 4;
uniform vec2 resolution; //resolution of screen
uniform vec3[LIGHT_COUNT] lightPos; //light position, normalized
uniform vec4[LIGHT_COUNT] lightColor; //light RGBA -- alpha is intensity
uniform vec4 ambientColor; //ambient RGBA -- alpha is intensity
void main() {
vec4 diffuseColor = texture2D(u_texture, vTexCoord);
vec3 normalMap = texture2D(u_normals, vTexCoord).rgb;
vec3 N = normalize(normalMap * 2.0 - 1.0);
float resolutionFactor = resolution.x / resolution.y;
vec3 diffuse = new vec3(0.0);
for (int i=0; i<LIGHT_COUNT; i++){
vec3 lightDir = vec3(lightPos[i].xy - (gl_FragCoord.xy / resolution.xy), lightPos[i].z);
lightDir.x *= resolutionFactor;
vec3 L = normalize(lightDir);
float distance = length(lightDir);
vec3 attenuation = 1.0 / ( 0.4 + 3.0*distance + (20.0*distance*distance ) );
diffuse += attenuation * (lightColor[i].rgb * lightColor[i].a) * max(dot(N, L), 0.0);
}
//pre-multiply ambient color with intensity
vec3 ambient = ambientColor.rgb * ambientColor.a;
//the calculation which brings it all together
vec3 intensity = min(vec3(1.0), ambient + diffuse); // don't remember if min is critical, but I think it might be to avoid shifting the hue when multiple lights add up to something very bright.
vec3 finalColor = diffuseColor.rgb * intensity;
gl_FragColor = vColor * vec4(finalColor, diffuseColor.a);
}
这取决于您对环境光的定义。如果每个光源“发射”环境光,则此行为完全正常。如果环境光是某种特殊的东西,只应添加一次,则应将其从灯光着色器中完全删除,并通过单独的绘制调用/着色器添加。正如注释所示:每个光源渲染每个几何体一次的方法效率非常低。考虑在一个着色器中使用统一数组。作为一个奥地利人也没什么不好:)谢谢你的快速回复:)我刚刚从着色器中删除了环境光。我现在如何实现它,而不使用其他着色器?您不能;)。创建第二个仅输出环境光的着色器并使用一次。我还应该在第一条评论中提到,如果在屏幕空间中有对象重叠,那么您的算法可能会出现问题,因为它们可能组合不正确。我现在了解了如何显示正确的环境光。我尝试运行20多个灯光,但性能非常差,但我不知道如何重写着色器以一次计算所有灯光。对于具有多个对象的场景,这种方法将很难保持。它的性能也很差。对可以处理多个灯光的着色器使用一个渲染调用。
static final int LIGHT_COUNT = 4;
final float[] tmpLightPositions = new float[3 * LIGHT_COUNT];
final float[] tmpLightColors = new float[4 * LIGHT_COUNT];
//...
int i = 0;
for (Vector3 pos : myLightPositions) {// should be LIGHT_COUNT of them
tmpLightPositions[i++] = pos.x;
tmpLightPositions[i++] = pos.y;
tmpLightPositions[i++] = pos.z;
}
i = 0;
for (Color col : myLightColors) {
tmpLightColors[i++] = color.r;
tmpLightColors[i++] = color.g;
tmpLightColors[i++] = color.b;
tmpLightColors[i++] = color.a;
}
shader.setUniform3fv("lightPos", tmpLightPositions, 0, tmpLightPositions.length);
shader.setUniform4fv("lightColor", tmpLightColors, 0, tmpLightColors.length);