From e1216e91cc52c9429430f7dcdb180e7dd0d9b087 Mon Sep 17 00:00:00 2001
From: Tony Wasserka <neobrainx@gmail.com>
Date: Tue, 23 Jul 2013 20:47:18 +0200
Subject: [PATCH] softgpu: Implement texture scaling, texture offset and
 texture coordinate wrapping/clamping.

---
 GPU/GPUState.h              |  4 ++++
 GPU/Software/Rasterizer.cpp | 36 ++++++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/GPU/GPUState.h b/GPU/GPUState.h
index f3a19cf6e4..d9495c1310 100644
--- a/GPU/GPUState.h
+++ b/GPU/GPUState.h
@@ -330,6 +330,10 @@ struct GPUgstate
 	int getUVProjMode() const { return (texmapmode >> 8) & 3;}   // 2 bits
 	int getUVLS0() const { return texshade & 0x3; }  // 2 bits
 	int getUVLS1() const { return (texshade >> 8) & 0x3; }  // 2 bits
+
+	bool isTexCoordClampedS() const { return texwrap & 1; }
+	bool isTexCoordClampedT() const { return (texwrap >> 8) & 1; }
+
 	int getScissorX1() const { return scissor1 & 0x3FF; }
 	int getScissorY1() const { return (scissor1 >> 10) & 0x3FF; }
 	int getScissorX2() const { return scissor2 & 0x3FF; }
diff --git a/GPU/Software/Rasterizer.cpp b/GPU/Software/Rasterizer.cpp
index e42a90d4f4..712de4c83b 100644
--- a/GPU/Software/Rasterizer.cpp
+++ b/GPU/Software/Rasterizer.cpp
@@ -100,11 +100,39 @@ static inline u32 SampleNearest(int level, float s, float t)
 
 	// TODO: Should probably check if textures are aligned properly...
 
-	// TODO: Not sure if that through mode treatment is correct..
-	unsigned int u = (gstate.isModeThrough()) ? s : s * width; // TODO: -1?
-	unsigned int v = (gstate.isModeThrough()) ? t : t * height; // TODO: -1?
+	unsigned int u, v;
+	if (gstate.isModeThrough()) {
+		// TODO: Is it really this simple?
+		u = s;
+		v = t;
+	} else {
+		if (gstate.getUVGenMode() == 0) {
+			s *= getFloat24(gstate.texscaleu);
+			t *= getFloat24(gstate.texscalev);
 
-	// TODO: texcoord wrapping!!
+			s += getFloat24(gstate.texoffsetu);
+			t += getFloat24(gstate.texoffsetv);
+
+			// TODO: Is this really only necessary for UV mapping?
+			if (gstate.isTexCoordClampedS()) {
+				if (s > 1.0) s = 1.0;
+				if (s < 0) s = 0;
+			} else {
+				// TODO: Does this work for negative coords?
+				s = fmod(s, 1.0f);
+			}
+			if (gstate.isTexCoordClampedT()) {
+				if (t > 1.0) t = 1.0;
+				if (t < 0.0) t = 0.0;
+			} else {
+				// TODO: Does this work for negative coords?
+				t = fmod(t, 1.0f);
+			}
+		}
+
+		u = s * width; // TODO: width-1 instead?
+		v = t * height; // TODO: width-1 instead?
+	}
 
 	// TODO: Assert tmap.tmn == 0 (uv texture mapping mode)