From e688bb2cdf9bfa8f73c762f500d6ab2ee3c36e92 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sun, 24 Oct 2021 12:27:47 -0700
Subject: [PATCH] GPU: Correct software transform projection.

Now reading the new fog value.
---
 GPU/Common/SoftwareTransformCommon.cpp | 10 ++++------
 GPU/Common/VertexShaderGenerator.cpp   | 16 ++++++++++++----
 GPU/GLES/ShaderManagerGLES.cpp         |  5 ++++-
 3 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/GPU/Common/SoftwareTransformCommon.cpp b/GPU/Common/SoftwareTransformCommon.cpp
index dfff93ac7d..2480224cb6 100644
--- a/GPU/Common/SoftwareTransformCommon.cpp
+++ b/GPU/Common/SoftwareTransformCommon.cpp
@@ -213,6 +213,7 @@ void SoftwareTransform::Decode(int prim, u32 vertType, const DecVtxFormat &decVt
 			// TODO: Write to a flexible buffer, we don't always need all four components.
 			TransformedVertex &vert = transformed[index];
 			reader.ReadPos(vert.pos);
+			vert.posw = 1.0f;
 
 			if (reader.hasColor0()) {
 				if (provokeIndOffset != 0 && index + provokeIndOffset < maxIndex) {
@@ -429,12 +430,9 @@ void SoftwareTransform::Decode(int prim, u32 vertType, const DecVtxFormat &decVt
 			fogCoef = (v[2] + fog_end) * fog_slope;
 
 			// TODO: Write to a flexible buffer, we don't always need all four components.
-			Vec4f projected;
-			Vec3ByMatrix44(projected.AsArray(), v, projMatrix_.m);
-			Vec3f viewportPos = projected.xyz() / projected.w;
-			memcpy(&transformed[index].x, viewportPos.AsArray(), 3 * sizeof(float));
-			transformed[index].posw = fogCoef;
-			memcpy(&transformed[index].u, uv, 3 * sizeof(float));
+			Vec3ByMatrix44(transformed[index].pos, v, projMatrix_.m);
+			transformed[index].fog = fogCoef;
+			memcpy(&transformed[index].uv, uv, 3 * sizeof(float));
 			transformed[index].color0_32 = c0.ToRGBA();
 			transformed[index].color1_32 = c1.ToRGBA();
 
diff --git a/GPU/Common/VertexShaderGenerator.cpp b/GPU/Common/VertexShaderGenerator.cpp
index 6ed7c2a5ca..419539ed27 100644
--- a/GPU/Common/VertexShaderGenerator.cpp
+++ b/GPU/Common/VertexShaderGenerator.cpp
@@ -236,11 +236,12 @@ bool GenerateVertexShader(const VShaderID &id, char *buffer, const ShaderLanguag
 		if (useHWTransform)
 			WRITE(p, "layout (location = %d) in vec3 position;\n", (int)PspAttributeLocation::POSITION);
 		else
-			// we pass the fog coord in w
 			WRITE(p, "layout (location = %d) in vec4 position;\n", (int)PspAttributeLocation::POSITION);
 
 		if (useHWTransform && hasNormal)
 			WRITE(p, "layout (location = %d) in vec3 normal;\n", (int)PspAttributeLocation::NORMAL);
+		if (!useHWTransform && enableFog)
+			WRITE(p, "layout (location = %d) in float fog;\n", (int)PspAttributeLocation::NORMAL);
 
 		if (doTexture && hasTexcoord) {
 			if (!useHWTransform && doTextureTransform && !isModeThrough) {
@@ -386,6 +387,9 @@ bool GenerateVertexShader(const VShaderID &id, char *buffer, const ShaderLanguag
 			if (lmode) {
 				WRITE(p, "  vec3 color1 : COLOR1;\n");
 			}
+			if (enableFog) {
+				WRITE(p, "  float fog : NORMAL;\n");
+			}
 			WRITE(p, "};\n");
 		}
 
@@ -435,6 +439,10 @@ bool GenerateVertexShader(const VShaderID &id, char *buffer, const ShaderLanguag
 			WRITE(p, "%s mediump vec3 normal;\n", compat.attribute);
 			*attrMask |= 1 << ATTR_NORMAL;
 		}
+		if (!useHWTransform && enableFog) {
+			WRITE(p, "%s highp float fog;\n", compat.attribute);
+			*attrMask |= 1 << ATTR_NORMAL;
+		}
 
 		if (doTexture && hasTexcoord) {
 			if (!useHWTransform && doTextureTransform && !isModeThrough) {
@@ -789,7 +797,7 @@ bool GenerateVertexShader(const VShaderID &id, char *buffer, const ShaderLanguag
 				WRITE(p, "  %sv_color1 = splat3(0.0);\n", compat.vsOutPrefix);
 		}
 		if (enableFog) {
-			WRITE(p, "  %sv_fogdepth = position.w;\n", compat.vsOutPrefix);
+			WRITE(p, "  %sv_fogdepth = fog;\n", compat.vsOutPrefix);
 		}
 		if (isModeThrough)	{
 			WRITE(p, "  vec4 outPos = mul(u_proj_through, vec4(position.xyz, 1.0));\n");
@@ -804,9 +812,9 @@ bool GenerateVertexShader(const VShaderID &id, char *buffer, const ShaderLanguag
 
 			// The viewport is used in this case, so need to compensate for that.
 			if (gstate_c.Supports(GPU_ROUND_DEPTH_TO_16BIT)) {
-				WRITE(p, "  vec4 outPos = depthRoundZVP(mul(displayRotation, vec4(position.xyz, 1.0)));\n");
+				WRITE(p, "  vec4 outPos = depthRoundZVP(mul(displayRotation, position));\n");
 			} else {
-				WRITE(p, "  vec4 outPos = mul(displayRotation, vec4(position.xyz, 1.0));\n");
+				WRITE(p, "  vec4 outPos = mul(displayRotation, position);\n");
 			}
 		}
 	} else {
diff --git a/GPU/GLES/ShaderManagerGLES.cpp b/GPU/GLES/ShaderManagerGLES.cpp
index 7392f7da10..7d59ee150f 100644
--- a/GPU/GLES/ShaderManagerGLES.cpp
+++ b/GPU/GLES/ShaderManagerGLES.cpp
@@ -85,7 +85,10 @@ LinkedShader::LinkedShader(GLRenderManager *render, VShaderID VSID, Shader *vs,
 	std::vector<GLRProgram::Semantic> semantics;
 	semantics.push_back({ ATTR_POSITION, "position" });
 	semantics.push_back({ ATTR_TEXCOORD, "texcoord" });
-	semantics.push_back({ ATTR_NORMAL, "normal" });
+	if (useHWTransform_)
+		semantics.push_back({ ATTR_NORMAL, "normal" });
+	else
+		semantics.push_back({ ATTR_NORMAL, "fog" });
 	semantics.push_back({ ATTR_W1, "w1" });
 	semantics.push_back({ ATTR_W2, "w2" });
 	semantics.push_back({ ATTR_COLOR0, "color0" });