OpenGL2: Bit more parallax optimization.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/renderergl2/glsl/lightall_fp.glsl b/src/renderergl2/glsl/lightall_fp.glsl
index d1155de4..d1182781 100644
--- a/src/renderergl2/glsl/lightall_fp.glsl
+++ b/src/renderergl2/glsl/lightall_fp.glsl
@@ -103,6 +103,9 @@ float RayIntersectDisplaceMap(vec2 dp, vec2 ds, sampler2D normalMap)
 	// texture depth at best depth
 	float texDepth = 0.0;
 
+	float prevT = SampleDepth(normalMap, dp);
+	float prevTexDepth = prevT;
+
 	// search front to back for first point inside object
 	for(int i = 0; i < linearSearchSteps - 1; ++i)
 	{
@@ -115,15 +118,16 @@ float RayIntersectDisplaceMap(vec2 dp, vec2 ds, sampler2D normalMap)
 			{
 				bestDepth = depth;	// store best depth
 				texDepth = t;
+				prevTexDepth = prevT;
 			}
+		prevT = t;
 	}
 
 	depth = bestDepth;
 
 #if !defined (USE_RELIEFMAP)
-	float prevDepth = depth - size;
-	float prevTexDepth = SampleDepth(normalMap, dp + ds * prevDepth);
-	bestDepth -= size * (prevDepth - prevTexDepth) / (size - texDepth + prevTexDepth);
+	float div = 1.0 / (1.0 + (prevTexDepth - texDepth) * float(linearSearchSteps));
+	bestDepth -= (depth - size - prevTexDepth) * div;
 #else
 	// recurse around first point (depth) for closest match
 	for(int i = 0; i < binarySearchSteps; ++i)
@@ -369,7 +373,7 @@ void main()
 	vec2 texCoords = var_TexCoords.xy;
 
 #if defined(USE_PARALLAXMAP)
-	vec3 offsetDir = normalize(E * tangentToWorld);
+	vec3 offsetDir = viewDir * tangentToWorld;
 
 	offsetDir.xy *= -u_NormalScale.a / offsetDir.z;