renderer: fix fog on GLSL 1.20

Author: illwieckz

src/engine/renderer/VertexSpecification.h

@@ -62,7 +62,7 @@ static const char* const attributeNames[] =
 	"attr_Position2",
 	"attr_QTangent2",
 	"attr_FogSurface",
-	"attr_FogPlanes", nullptr, nullptr, nullptr, nullptr,
+	"attr_FogPlane0", "attr_FogPlane1", "attr_FogPlane2", "attr_FogPlane3", "attr_FogPlane4",
 };
 
 enum

src/engine/renderer/glsl_source/fog_fp.glsl

@@ -32,7 +32,14 @@ IN(flat) vec4 var_FogSurface;
 
 #ifdef OUTSIDE_FOG
 #define NUM_PLANES 5
-IN(flat) vec4 var_FogPlanes[NUM_PLANES];
+
+/* Not supported on GLSL 1.20:
+IN(flat) vec4 var_FogPlanes[NUM_PLANES]; */
+IN(flat) vec4 var_FogPlane0;
+IN(flat) vec4 var_FogPlane1;
+IN(flat) vec4 var_FogPlane2;
+IN(flat) vec4 var_FogPlane3;
+IN(flat) vec4 var_FogPlane4;
 #endif
 
 uniform sampler2D	u_DepthMap;
@@ -49,11 +56,19 @@ DECLARE_OUTPUT(vec4)
 // Trace against the inner sides of the fog brush
 float FogDistance(vec3 start, vec3 dir)
 {
+	vec4 fogPlanes[NUM_PLANES];
+	fogPlanes[0] = var_FogPlane0;
+	fogPlanes[1] = var_FogPlane1;
+	fogPlanes[2] = var_FogPlane2;
+	fogPlanes[3] = var_FogPlane3;
+	fogPlanes[4] = var_FogPlane4;
+
 	vec4 start4 = vec4(-start, 1.0);
 	float minDist = 1.0e20;
 	for (int i = 0; i < NUM_PLANES; i++)
 	{
-		float dist = dot(start4, var_FogPlanes[i]) / dot(dir, var_FogPlanes[i].xyz) ;
+		float dist = dot(start4, fogPlanes[i]) / dot(dir, fogPlanes[i].xyz) ;
+
 		if (dist >= 0.0)
 		{
 			minDist = min(minDist, dist);

src/engine/renderer/glsl_source/fog_vp.glsl

@@ -41,9 +41,21 @@ OUT(smooth) vec3 var_Position;
 OUT(flat) vec4 var_FogSurface;
 
 #ifdef OUTSIDE_FOG
-#define NUM_PLANES 5
-IN vec4 attr_FogPlanes[NUM_PLANES];
-OUT(flat) vec4 var_FogPlanes[NUM_PLANES];
+/* Not supported on GLSL 1.20:
+IN(flat) attr_FogPlanes[NUM_PLANES]; */
+IN vec4 attr_FogPlane0;
+IN vec4 attr_FogPlane1;
+IN vec4 attr_FogPlane2;
+IN vec4 attr_FogPlane3;
+IN vec4 attr_FogPlane4;
+
+/* Not supported on GLSL 1.20:
+OUT(flat) var_FogPlanes[NUM_PLANES]; */
+OUT(flat) vec4 var_FogPlane0;
+OUT(flat) vec4 var_FogPlane1;
+OUT(flat) vec4 var_FogPlane2;
+OUT(flat) vec4 var_FogPlane3;
+OUT(flat) vec4 var_FogPlane4;
 #endif
 
 void main()
@@ -54,9 +66,10 @@ void main()
 	var_FogSurface = attr_FogSurface;
 
 	#ifdef OUTSIDE_FOG
-		for (int i = 0; i < NUM_PLANES; i++)
-		{
-			var_FogPlanes[i] = attr_FogPlanes[i];
-		}
+		var_FogPlane0 = attr_FogPlane0;
+		var_FogPlane1 = attr_FogPlane1;
+		var_FogPlane2 = attr_FogPlane2;
+		var_FogPlane3 = attr_FogPlane3;
+		var_FogPlane4 = attr_FogPlane4;
 	#endif
 }