From e5da13f14635b6accc5eefd6986de03d2cff9662 Mon Sep 17 00:00:00 2001
From: James Canete <SmileTheory@gmail.com>
Date: Fri, 21 Dec 2018 19:53:18 -0800
Subject: [PATCH] OpenGL2: r_cubemapping 2 for box cubemap parallax.

---
 code/renderergl2/glsl/lightall_fp.glsl | 34 ++++++++++++++++++++++++++
 code/renderergl2/tr_glsl.c             |  6 +++++
 2 files changed, 40 insertions(+)

diff --git a/code/renderergl2/glsl/lightall_fp.glsl b/code/renderergl2/glsl/lightall_fp.glsl
index 6465bd84..d77cd7c7 100644
--- a/code/renderergl2/glsl/lightall_fp.glsl
+++ b/code/renderergl2/glsl/lightall_fp.glsl
@@ -194,6 +194,36 @@ float CalcLightAttenuation(float point, float normDist)
 }
 
 
+vec4 hitCube(vec3 ray, vec3 pos, vec3 invSize, float lod, samplerCube tex)
+{
+	// find any hits on cubemap faces facing the camera
+	vec3 scale = (sign(ray) - pos) / ray;
+
+	// find the nearest hit
+	float minScale = min(min(scale.x, scale.y), scale.z);
+
+	// if the nearest hit is behind the camera, ignore
+	// should not be necessary as long as pos is inside the cube
+	//if (minScale < 0.0)
+		//return vec4(0.0);
+
+	// calculate the hit position, that's our texture coordinates
+	vec3 tc = pos + ray * minScale;
+
+	// if the texture coordinates are outside the cube, ignore
+	// necessary since we're not fading out outside the cube
+	if (any(greaterThan(abs(tc), vec3(1.00001))))
+		return vec4(0.0);
+
+	// fade out when approaching the cubemap edges
+	//vec3 fade3 = abs(pos);
+	//float fade = max(max(fade3.x, fade3.y), fade3.z);
+	//fade = clamp(1.0 - fade, 0.0, 1.0);
+			
+	//return vec4(textureCubeLod(tex, tc, lod).rgb * fade, fade);
+	return vec4(textureCubeLod(tex, tc, lod).rgb, 1.0);
+}
+
 void main()
 {
 	vec3 viewDir, lightColor, ambientColor, reflectance;
@@ -374,7 +404,11 @@ void main()
 	// from http://seblagarde.wordpress.com/2012/09/29/image-based-lighting-approaches-and-parallax-corrected-cubemap/
 	vec3 parallax = u_CubeMapInfo.xyz + u_CubeMapInfo.w * viewDir;
 
+  #if defined(USE_BOX_CUBEMAP_PARALLAX)
+	vec3 cubeLightColor = hitCube(R * u_CubeMapInfo.w, parallax, u_CubeMapInfo.www, ROUGHNESS_MIPS * roughness, u_CubeMap).rgb * u_EnableTextures.w;
+  #else
 	vec3 cubeLightColor = textureCubeLod(u_CubeMap, R + parallax, ROUGHNESS_MIPS * roughness).rgb * u_EnableTextures.w;
+  #endif
 
 	// normalize cubemap based on last roughness mip (~diffuse)
 	// multiplying cubemap values by lighting below depends on either this or the cubemap being normalized at generation
diff --git a/code/renderergl2/tr_glsl.c b/code/renderergl2/tr_glsl.c
index 218017de..4ed49370 100644
--- a/code/renderergl2/tr_glsl.c
+++ b/code/renderergl2/tr_glsl.c
@@ -1129,9 +1129,15 @@ void GLSL_InitGPUShaders(void)
 				Q_strcat(extradefines, 1024, "#define USE_SPECULARMAP\n");
 
 			if (r_cubeMapping->integer)
+			{
 				Q_strcat(extradefines, 1024, "#define USE_CUBEMAP\n");
+				if (r_cubeMapping->integer == 2)
+					Q_strcat(extradefines, 1024, "#define USE_BOX_CUBEMAP_PARALLAX\n");
+			}
 			else if (r_deluxeSpecular->value > 0.000001f)
+			{
 				Q_strcat(extradefines, 1024, va("#define r_deluxeSpecular %f\n", r_deluxeSpecular->value));
+			}
 
 			switch (r_glossType->integer)
 			{