Box projection support for IBL probes

data/__internal/shaders/EnvironmentProbe/EnvironmentProbe.frag.glsl

@@ -22,6 +22,10 @@ uniform vec4 fogColor;
 uniform float fogStart;
 uniform float fogEnd;
 
+uniform bool useBoxProjection;
+uniform vec3 boxSize;
+uniform vec3 boxPosition;
+
 #include <unproject.glsl>
 #include <gamma.glsl>
 #include <fresnel.glsl>
@@ -64,6 +68,20 @@ subroutine uniform srtAmbient ambient;
 uniform sampler2D ambientBRDF;
 uniform bool haveAmbientBRDF;
 
+vec3 bpcm(in vec3 pos, in vec3 v, vec3 boxMax, vec3 boxMin, vec3 boxPos)
+{
+    vec3 nrdir = v;
+    vec3 rbmax = (boxMax - pos) / nrdir;
+    vec3 rbmin = (boxMin - pos) / nrdir;
+    vec3 rbminmax;
+    rbminmax.x = (nrdir.x > 0.0)? rbmax.x : rbmin.x;
+    rbminmax.y = (nrdir.y > 0.0)? rbmax.y : rbmin.y;
+    rbminmax.z = (nrdir.z > 0.0)? rbmax.z : rbmin.z;
+    float fa = min(min(rbminmax.x, rbminmax.y), rbminmax.z);
+    vec3 posOnBox = pos + nrdir * fa;
+    return posOnBox - boxPos;
+}
+
 layout(location = 0) out vec4 fragColor;
 
 void main()
@@ -99,6 +117,14 @@ void main()
     vec3 worldN = normalize((vec4(N, 0.0) * viewMatrix).xyz);
     vec3 worldR = reflect(worldE, worldN);
 
+    if (useBoxProjection)
+    {
+        vec3 boxMin = boxPosition - boxSize;
+        vec3 boxMax = boxPosition + boxSize;
+        //worldN = normalize(bpcm(worldPos, worldN, boxMax, boxMin, boxPosition));
+        worldR = normalize(bpcm(worldPos, worldR, boxMax, boxMin, boxPosition));
+    }
+
     vec4 pbr = texture(pbrBuffer, gbufTexCoord);
     float roughness = pbr.r;
     float metallic = pbr.g;

src/dagon/graphics/entity.d

@@ -75,6 +75,7 @@ class Entity: Owner, Updateable
     bool dynamic = true;
     bool decal = false;
     bool probe = false;
+    bool probeUseBoxProjection = false;
     bool transparent = false;
     float opacity = 1.0f;
     float gbufferMask = 1.0f;

src/dagon/render/deferred/passes/probe.d

@@ -84,6 +84,7 @@ class PassEnvironmentProbe: RenderPass
             {
                 if (entity.visible && entity.drawable)
                 {
+                    environmentProbeShader.useBoxProjection = entity.probeUseBoxProjection;
                     renderEntity(entity, environmentProbeShader);
                 }
             }

src/dagon/render/deferred/shaders/probe.d

@@ -47,6 +47,8 @@ import dagon.graphics.state;
 class EnvironmentProbeShader: Shader
 {
     String vs, fs;
+
+    bool useBoxProjection = false;
 
     this(Owner owner)
     {
@@ -154,6 +156,12 @@ class EnvironmentProbeShader: Shader
         }
 
         setParameter("ambientEnergy", mat.emissionEnergy);
+
+        Vector3f boxSize = state.modelMatrix.scaling;
+        Vector3f boxPosition = state.modelMatrix.translation;
+        setParameter("boxSize", boxSize);
+        setParameter("boxPosition", boxPosition);
+        setParameter("useBoxProjection", useBoxProjection);
 
         // Texture 6 - occlusion buffer
         glActiveTexture(GL_TEXTURE6);