From 370e938520872f60e80e896058eaf89c5309f615 Mon Sep 17 00:00:00 2001
From: fincs <fincs.alt1@gmail.com>
Date: Thu, 30 Mar 2017 23:39:39 +0200
Subject: [PATCH] LightLut/LightEnv: generate/use proper LUTs for the [0,1]
 domain

---
 include/c3d/light.h |  2 +-
 source/lightenv.c   |  4 ++--
 source/lightlut.c   | 16 +++++++++-------
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/include/c3d/light.h b/include/c3d/light.h
index c2ec4e8..da13c04 100644
--- a/include/c3d/light.h
+++ b/include/c3d/light.h
@@ -62,7 +62,7 @@ void C3D_LightEnvBind(C3D_LightEnv* env);
 
 void C3D_LightEnvMaterial(C3D_LightEnv* env, const C3D_Material* mtl);
 void C3D_LightEnvAmbient(C3D_LightEnv* env, float r, float g, float b);
-void C3D_LightEnvLut(C3D_LightEnv* env, int lutId, int input, bool abs, C3D_LightLut* lut);
+void C3D_LightEnvLut(C3D_LightEnv* env, GPU_LIGHTLUTID lutId, GPU_LIGHTLUTINPUT input, bool negative, C3D_LightLut* lut);
 
 enum
 {
diff --git a/source/lightenv.c b/source/lightenv.c
index 8ecf05f..20ccdde 100644
--- a/source/lightenv.c
+++ b/source/lightenv.c
@@ -192,7 +192,7 @@ void C3D_LightEnvAmbient(C3D_LightEnv* env, float r, float g, float b)
 	env->flags |= C3DF_LightEnv_MtlDirty;
 }
 
-void C3D_LightEnvLut(C3D_LightEnv* env, int lutId, int input, bool abs, C3D_LightLut* lut)
+void C3D_LightEnvLut(C3D_LightEnv* env, GPU_LIGHTLUTID lutId, GPU_LIGHTLUTINPUT input, bool negative, C3D_LightLut* lut)
 {
 	static const s8 ids[] = { 0, 1, -1, 2, 3, 4, 5, -1 };
 	int id = ids[lutId];
@@ -215,7 +215,7 @@ void C3D_LightEnvLut(C3D_LightEnv* env, int lutId, int input, bool abs, C3D_Ligh
 
 	u32 absbit = 1 << (lutId*4 + 1);
 	env->conf.lutInput.abs &= ~absbit;
-	if (!abs)
+	if (negative)
 		env->conf.lutInput.abs |= absbit;
 
 	env->flags |= C3DF_LightEnv_Dirty;
diff --git a/source/lightlut.c b/source/lightlut.c
index 7b16746..6c34a3a 100644
--- a/source/lightlut.c
+++ b/source/lightlut.c
@@ -35,15 +35,17 @@ void LightLut_FromFunc(C3D_LightLut* lut, C3D_LightLutFunc func, float param, bo
 	int i;
 	float data[512];
 	memset(data, 0, sizeof(data));
-	int start = negative ? (-128) : 0;
-	for (i = start; i <= 128; i ++)
+	int min = negative ? (-128) : 0;
+	int max = negative ?   128  : 256;
+	for (i = min; i <= max; i ++)
 	{
-		float x   = i/128.0f;
+		float x   = (float)i/max;
 		float val = func(x, param);
-		if (i < 128)
-			data[i & 0xFF] = val;
-		if (i > start)
-			data[(i & 0xFF) + 255] = val - data[(i-1) & 0xFF];
+		int   idx = negative ? (i & 0xFF) : i;
+		if (i < max)
+			data[idx] = val;
+		if (i > min)
+			data[idx+255] = val-data[idx-1];
 	}
 	LightLut_FromArray(lut, data);
 }