OpenGL2: Use RGBM instead of RGBE encoding for lightmaps.

4 files changed, 26 insertions, 38 deletions

diff --git a/src/renderergl2/glsl/generic_fp.glsl b/src/renderergl2/glsl/generic_fp.glsl
index dea52e06..997d4daa 100644
--- a/src/renderergl2/glsl/generic_fp.glsl
+++ b/src/renderergl2/glsl/generic_fp.glsl
@@ -20,8 +20,8 @@ void main()
 	vec4 color  = texture2D(u_DiffuseMap, var_DiffuseTex);
 #if defined(USE_LIGHTMAP)
 	vec4 color2 = texture2D(u_LightMap, var_LightTex);
-  #if defined(RGBE_LIGHTMAP)
-	color2.rgb *= exp2(color2.a * 255.0 - 128.0);
+  #if defined(RGBM_LIGHTMAP)
+	color2.rgb *= 32.0 * color2.a;
 	color2.a = 1.0;
   #endif
 
diff --git a/src/renderergl2/glsl/lightall_fp.glsl b/src/renderergl2/glsl/lightall_fp.glsl
index efd01399..6aec2b4a 100644
--- a/src/renderergl2/glsl/lightall_fp.glsl
+++ b/src/renderergl2/glsl/lightall_fp.glsl
@@ -285,8 +285,8 @@ void main()
 
 #if defined(USE_LIGHTMAP)
 	vec4 lightSample = texture2D(u_LightMap, var_LightTex).rgba;
-  #if defined(RGBE_LIGHTMAP)
-	lightSample.rgb *= exp2(lightSample.a * 255.0 - 128.0);
+  #if defined(RGBM_LIGHTMAP)
+	lightSample.rgb *= 32.0 * lightSample.a;
   #endif
 	vec3 lightColor = lightSample.rgb;
 #elif defined(USE_LIGHT_VECTOR) && !defined(USE_FAST_LIGHT)
diff --git a/src/renderergl2/tr_bsp.c b/src/renderergl2/tr_bsp.c
index f1eb51e3..1fcf817f 100644
--- a/src/renderergl2/tr_bsp.c
+++ b/src/renderergl2/tr_bsp.c
@@ -143,49 +143,32 @@ static void R_ColorShiftLightingFloats(float in[4], float out[4], float scale )
 	out[3] = in[3];
 }
 
-
-void ColorToRGBE(const vec3_t color, unsigned char rgbe[4])
+// Modified from http://graphicrants.blogspot.jp/2009/04/rgbm-color-encoding.html
+void ColorToRGBM(const vec3_t color, unsigned char rgbm[4])
 {
 	vec3_t          sample;
 	float			maxComponent;
-	int				e;
 
-	VectorCopy(color, sample);
+	VectorScale(color, 1.0f / 32.0f, sample);
 
 	maxComponent = sample[0];
 	if(sample[1] > maxComponent)
 		maxComponent = sample[1];
 	if(sample[2] > maxComponent)
 		maxComponent = sample[2];
+	if(0.000001f > maxComponent)
+		maxComponent = 0.000001f;
+	if(maxComponent > 1.0f)
+		maxComponent = 1.0f;
 
-	if(maxComponent < 1e-32)
-	{
-		rgbe[0] = 0;
-		rgbe[1] = 0;
-		rgbe[2] = 0;
-		rgbe[3] = 0;
-	}
-	else
-	{
-#if 0
-		maxComponent = frexp(maxComponent, &e) * 255.0 / maxComponent;
-		rgbe[0] = (unsigned char) (sample[0] * maxComponent);
-		rgbe[1] = (unsigned char) (sample[1] * maxComponent);
-		rgbe[2] = (unsigned char) (sample[2] * maxComponent);
-		rgbe[3] = (unsigned char) (e + 128);
-#else
-		e = ceil(log(maxComponent) / log(2.0f));//ceil(log2(maxComponent));
-		VectorScale(sample, 1.0 / pow(2.0f, e)/*exp2(e)*/, sample);
+	VectorScale(sample, 1.0f / maxComponent, sample);
 
-		rgbe[0] = (unsigned char) (sample[0] * 255);
-		rgbe[1] = (unsigned char) (sample[1] * 255);
-		rgbe[2] = (unsigned char) (sample[2] * 255);
-		rgbe[3] = (unsigned char) (e + 128);
-#endif
-	}
+	rgbm[0] = (unsigned char) (sample[0] * 255);
+	rgbm[1] = (unsigned char) (sample[1] * 255);
+	rgbm[2] = (unsigned char) (sample[2] * 255);
+	rgbm[3] = (unsigned char) (maxComponent * 255);
 }
 
-
 void ColorToRGBA16F(const vec3_t color, unsigned short rgba16f[4])
 {
 	rgba16f[0] = FloatToHalf(color[0]);
@@ -291,8 +274,13 @@ static	void R_LoadLightmaps( lump_t *l, lump_t *surfs ) {
 		tr.deluxemaps = ri.Hunk_Alloc( tr.numLightmaps * sizeof(image_t *), h_low );
 	}
 
-	if (r_hdr->integer && glRefConfig.textureFloat && glRefConfig.halfFloatPixel)
-		textureInternalFormat = GL_RGBA16F_ARB;
+	if (r_hdr->integer)
+	{
+		if (glRefConfig.textureFloat && glRefConfig.halfFloatPixel)
+			textureInternalFormat = GL_RGBA16F_ARB;
+		else
+			textureInternalFormat = GL_RGBA8;
+	}
 
 	if (r_mergeLightmaps->integer)
 	{
@@ -430,7 +418,7 @@ static	void R_LoadLightmaps( lump_t *l, lump_t *surfs ) {
 					if (glRefConfig.textureFloat && glRefConfig.halfFloatPixel)
 						ColorToRGBA16F(color, (unsigned short *)(&image[j*8]));
 					else
-						ColorToRGBE(color, &image[j*4]);
+						ColorToRGBM(color, &image[j*4]);
 				}
 				else
 				{
diff --git a/src/renderergl2/tr_glsl.c b/src/renderergl2/tr_glsl.c
index 38eb7f6d..a2707cd0 100644
--- a/src/renderergl2/tr_glsl.c
+++ b/src/renderergl2/tr_glsl.c
@@ -908,7 +908,7 @@ void GLSL_InitGPUShaders(void)
 			Q_strcat(extradefines, 1024, "#define USE_LIGHTMAP\n");
 
 		if (r_hdr->integer && !(glRefConfig.textureFloat && glRefConfig.halfFloatPixel))
-			Q_strcat(extradefines, 1024, "#define RGBE_LIGHTMAP\n");
+			Q_strcat(extradefines, 1024, "#define RGBM_LIGHTMAP\n");
 
 		if (!GLSL_InitGPUShader(&tr.genericShader[i], "generic", attribs, qtrue, extradefines, qtrue, fallbackShader_generic_vp, fallbackShader_generic_fp))
 		{
@@ -1037,7 +1037,7 @@ void GLSL_InitGPUShaders(void)
 		}
 
 		if (r_hdr->integer && !(glRefConfig.textureFloat && glRefConfig.halfFloatPixel))
-			Q_strcat(extradefines, 1024, "#define RGBE_LIGHTMAP\n");
+			Q_strcat(extradefines, 1024, "#define RGBM_LIGHTMAP\n");
 
 		if (i & LIGHTDEF_LIGHTTYPE_MASK)
 		{