rayleigh: fix per-vertex calculations

data/shaders/opengl/basesphere_uniforms.glsl

@@ -32,8 +32,6 @@ layout(std140) uniform BaseSphereData {
 	Eclipse eclipse;
 };
 
-#ifdef FRAGMENT_SHADER
-
 // NOTE: you must include attributes.glsl first!
 
 // Common code to calculate the diffuse light term for a planet's surface
@@ -50,6 +48,8 @@ void CalcPlanetDiffuse(inout vec4 diff, in vec4 color, in vec3 L, in vec3 N, in
 	diff += color * uneclipsed * 0.5 * clampedCosine;
 }
 
+#ifdef FRAGMENT_SHADER
+
 // Common code to calculate the specular light term for a planet's surface
 // L: light -> surface vector (normalized)
 // N: surface normal

data/shaders/opengl/rayleigh_fast.frag

@@ -6,41 +6,14 @@
 #include "basesphere_uniforms.glsl"
 #include "rayleigh.glsl"
 
-uniform int NumShadows;
-
 in vec4 varyingEyepos;
 in vec4 vertexColor;
 
 out vec4 frag_color;
 
 void main(void)
 {
-	float skyNear, skyFar;
-	vec3 eyenorm = normalize(varyingEyepos.xyz);
-
-	sphereEntryExitDist(skyNear, skyFar, geosphereCenter, varyingEyepos.xyz, geosphereRadius * geosphereAtmosTopRad);
-
-	// a&b scaled so length of 1.0 means planet surface.
-	vec3 a = (skyNear * eyenorm - geosphereCenter) * geosphereInvRadius;
-	vec3 b = (skyFar * eyenorm - geosphereCenter) * geosphereInvRadius;
-
-	vec4 atmosDiffuse = vec4(0.0);
-
-#if (NUM_LIGHTS > 0)
-	vec3 surfaceNorm = normalize(skyNear * eyenorm - geosphereCenter);
-	for (int i=0; i<NUM_LIGHTS; ++i) {
-		vec3 lightDir = normalize(vec3(uLight[i].position));
-
-		float uneclipsed = clamp(calcUneclipsedSky(eclipse, NumShadows, a, b, lightDir), 0.0, 1.0);
-
-		float nDotVP =  max(0.0, dot(surfaceNorm, lightDir));
-		float nnDotVP = max(0.0, dot(surfaceNorm, -lightDir));  //need backlight to increase horizon
-		atmosDiffuse +=  uLight[i].diffuse * uneclipsed * 0.5*(nDotVP+0.5*clamp(1.0-nnDotVP*4.0,0.0,1.0) * INV_NUM_LIGHTS);
-	}
-#endif
+    vec4 color = vec4(vertexColor.rgb, 1.0) * 20;
 
-	atmosDiffuse.a = 1.0;
-	frag_color = (atmosDiffuse *
-		vec4(vertexColor.rgb, 1.0) * 20
-		);
+    frag_color = toSRGB(1 - exp(-color));
 }

data/shaders/opengl/rayleigh_fast.vert

@@ -6,6 +6,8 @@
 #include "basesphere_uniforms.glsl"
 #include "rayleigh.glsl"
 
+uniform int NumShadows;
+
 out vec4 varyingEyepos;
 out vec4 vertexColor;
 
@@ -18,14 +20,28 @@ void main(void)
 	vec3 eyenorm = normalize(varyingEyepos.xyz);
 	vec3 specularHighlight = vec3(0.0);
 
-	vec2 skyDist = raySphereIntersect(geosphereCenter, eyenorm, geosphereAtmosTopRad);
+	vec2 atmosDist = raySphereIntersect(geosphereCenter, eyenorm, geosphereAtmosTopRad);
+
+	// a&b scaled so length of 1.0 means planet surface.
+	vec3 a = atmosDist.x * eyenorm - geosphereCenter;
+	vec3 b = atmosDist.y * eyenorm - geosphereCenter;
+
+	float AU = 149598000000.0;
 
 #if (NUM_LIGHTS > 0)
 	for (int i=0; i<NUM_LIGHTS; ++i) {
 		vec3 lightDir = normalize(vec3(uLight[i].position));
 
-		vec3 sphereCenter = geosphereCenter * geosphereRadius;
-		specularHighlight += computeIncidentLight(lightDir, eyenorm, sphereCenter, skyDist) * INV_NUM_LIGHTS;
+		float uneclipsed = clamp(calcUneclipsedSky(eclipse, NumShadows, a, b, lightDir), 0.0, 1.0);
+
+		// Convert from radius-relative to real coordinates
+		vec3 center = geosphereCenter * geosphereRadius;
+
+		vec3 lightPosAU = uLight[i].position.xyz / AU;
+		float intensity = 1.f / dot(lightPosAU, lightPosAU); // magic to avoid calculating length and then squaring it
+
+		specularHighlight += computeIncidentLight(lightDir, eyenorm, center, atmosDist, toLinear(uLight[i].diffuse), uneclipsed) * intensity;
+
 	}
 #endif