| float calculateDiffuseAreaOld(in vec3 lightDir, in vec3 lightPos, in vec4 lightUp, |
| in vec4 lightRt, in vec3 worldPos, out vec3 outDir) |
| { |
| if ( dot( worldPos-lightPos, lightDir) < 0.0 ) |
| return 0.0; |
| |
| vec3 v0 = lightPos - (lightRt.xyz * lightRt.w * 0.5) - (lightUp.xyz * lightUp.w * 0.5); |
| vec3 v1 = lightPos - (lightRt.xyz * lightRt.w * 0.5) + (lightUp.xyz * lightUp.w * 0.5); |
| vec3 v2 = lightPos + (lightRt.xyz * lightRt.w * 0.5) + (lightUp.xyz * lightUp.w * 0.5); |
| vec3 v3 = lightPos + (lightRt.xyz * lightRt.w * 0.5) - (lightUp.xyz * lightUp.w * 0.5); |
| v0 = normalize( v0 - worldPos ); v1 = normalize( v1 - worldPos ); |
| v2 = normalize( v2 - worldPos ); v3 = normalize( v3 - worldPos ); |
| |
| float a01 = acos( clamp( dot(v0, v1), -1.0, 1.0 ) ); |
| float a12 = acos( clamp( dot(v1, v2), -1.0, 1.0 ) ); |
| float a23 = acos( clamp( dot(v2, v3), -1.0, 1.0 ) ); |
| float a30 = acos( clamp( dot(v3, v0), -1.0, 1.0 ) ); |
| |
| outDir = vec3( 0.0 ); |
| outDir -= normalize(cross( v0, v1 )) * a01; |
| outDir -= normalize(cross( v1, v2 )) * a12; |
| outDir -= normalize(cross( v2, v3 )) * a23; |
| outDir -= normalize(cross( v3, v0 )) * a30; |
| |
| float retVal = length(outDir) * 0.15915494309; // solid angle / 2*pi |
| outDir = normalize(outDir); |
| retVal *= clamp( dot( worldPos-lightPos, lightDir), 0.0, 1.0 ); |
| return retVal; |
| } |