Rename viewportX1/X2 etc to scale + center, which is what they actually are.

GPU/Common/DrawEngineCommon.cpp

@@ -66,20 +66,19 @@ static void PlanesFromMatrix(float mtx[16], Plane planes[6]) {
 }
 
 static Vec3f ClipToScreen(const Vec4f& coords) {
-	// TODO: Check for invalid parameters (x2 < x1, etc)
+	float xScale = gstate.getViewportXScale();
-	float vpx1 = gstate.getViewportX1();
+	float xCenter = gstate.getViewportXCenter();
-	float vpx2 = gstate.getViewportX2();
+	float yScale = gstate.getViewportYScale();
-	float vpy1 = gstate.getViewportY1();
+	float yCenter = gstate.getViewportYCenter();
-	float vpy2 = gstate.getViewportY2();
+	float zScale = gstate.getViewportZScale();
-	float vpz1 = gstate.getViewportZ1();
+	float zCenter = gstate.getViewportZCenter();
-	float vpz2 = gstate.getViewportZ2();
 
-	float retx = coords.x * vpx1 / coords.w + vpx2;
+	float x = coords.x * xScale / coords.w + xCenter;
-	float rety = coords.y * vpy1 / coords.w + vpy2;
+	float y = coords.y * yScale / coords.w + yCenter;
-	float retz = coords.z * vpz1 / coords.w + vpz2;
+	float z = coords.z * zScale / coords.w + zCenter;
 
 	// 16 = 0xFFFF / 4095.9375
-	return Vec3f(retx * 16, rety * 16, retz);
+	return Vec3f(x * 16, y * 16, z);
 }
 
 static Vec3f ScreenToDrawing(const Vec3f& coords) {

GPU/Common/FramebufferCommon.cpp

@@ -240,8 +240,8 @@ void GetFramebufferHeuristicInputs(FramebufferHeuristicParams *params, const GPU
 	params->isModeThrough = gstate.isModeThrough();
 
 	// Viewport-X1 and Y1 are not the upper left corner, but half the width/height. A bit confusing.
-	params->viewportWidth = (int)(fabsf(gstate.getViewportX1()*2.0f));
+	params->viewportWidth = (int)(fabsf(gstate.getViewportXScale()*2.0f));
-	params->viewportHeight = (int)(fabsf(gstate.getViewportY1()*2.0f));
+	params->viewportHeight = (int)(fabsf(gstate.getViewportYScale()*2.0f));
 	params->regionWidth = gstate.getRegionX2() + 1;
 	params->regionHeight = gstate.getRegionY2() + 1;
 	params->scissorWidth = gstate.getScissorX2() + 1;

GPU/Directx9/ShaderManagerDX9.cpp

@@ -309,8 +309,8 @@ void ShaderManagerDX9::VSUpdateUniforms(int dirtyUniforms) {
 		// In Phantasy Star Portable 2, depth range sometimes goes negative and is clamped by glDepthRange to 0,
 		// causing graphics clipping glitch (issue #1788). This hack modifies the projection matrix to work around it.
 		if (g_Config.bDepthRangeHack) {
-			float zScale = gstate.getViewportZ1() / 65535.0f;
+			float zScale = gstate.getViewportZScale() / 65535.0f;
-			float zCenter = gstate.getViewportZ2() / 65535.0f;
+			float zCenter = gstate.getViewportZCenter() / 65535.0f;
 
 			// if far depth range < 0
 			if (zCenter + zScale < 0.0f) {

GPU/Directx9/StateMappingDX9.cpp

@@ -718,10 +718,10 @@ void TransformDrawEngineDX9::ApplyDrawState(int prim) {
 			(regionY2 - regionY1) * renderHeightFactor,
 			0.f, 1.f);
 	} else {
-		float vpXScale = gstate.getViewportX1();
+		float vpXScale = gstate.getViewportXScale();
-		float vpXCenter = gstate.getViewportX2();
+		float vpXCenter = gstate.getViewportXCenter();
-		float vpYScale = gstate.getViewportY1();
+		float vpYScale = gstate.getViewportYScale();
-		float vpYCenter = gstate.getViewportY2();
+		float vpYCenter = gstate.getViewportYCenter();
 
 		// The viewport transform appears to go like this: 
 		// Xscreen = -offsetX + vpXCenter + vpXScale * Xview
@@ -742,9 +742,10 @@ void TransformDrawEngineDX9::ApplyDrawState(int prim) {
 		vpWidth *= renderWidthFactor;
 		vpHeight *= renderHeightFactor;
 
-		float zScale = gstate.getViewportZ1() / 65535.0f;
+		float zScale = gstate.getViewportZScale() / 65535.0f;
-		float zCenter = gstate.getViewportZ2() / 65535.0f;
+		float zCenter = gstate.getViewportZCenter() / 65535.0f;
 
+		// Note - we lose the sign of the zscale here. Although I suppose we still keep it in gstate_c.vpDepth...
 		float depthRangeMin = zCenter - fabsf(zScale);
 		float depthRangeMax = zCenter + fabsf(zScale);
 
@@ -807,4 +808,4 @@ void TransformDrawEngineDX9::ApplyDrawState(int prim) {
 	}
 }
 
-};
+}

GPU/GLES/ShaderManager.cpp

@@ -406,8 +406,8 @@ void LinkedShader::UpdateUniforms(u32 vertType) {
 		// In Phantasy Star Portable 2, depth range sometimes goes negative and is clamped by glDepthRange to 0,
 		// causing graphics clipping glitch (issue #1788). This hack modifies the projection matrix to work around it.
 		if (g_Config.bDepthRangeHack) {
-			float zScale = gstate.getViewportZ1() / 65535.0f;
+			float zScale = gstate.getViewportZScale() / 65535.0f;
-			float zCenter = gstate.getViewportZ2() / 65535.0f;
+			float zCenter = gstate.getViewportZCenter() / 65535.0f;
 
 			// if far depth range < 0
 			if (zCenter + zScale < 0.0f) {

GPU/GLES/StateMapping.cpp

@@ -792,10 +792,10 @@ void TransformDrawEngine::ApplyDrawState(int prim) {
 		glstate.depthRange.set(0.0f, 1.0f);
 	} else {
 		// These we can turn into a glViewport call, offset by offsetX and offsetY. Math after.
-		float vpXScale = gstate.getViewportX1();
+		float vpXScale = gstate.getViewportXScale();
-		float vpXCenter = gstate.getViewportX2();
+		float vpXCenter = gstate.getViewportXCenter();
-		float vpYScale = gstate.getViewportY1();
+		float vpYScale = gstate.getViewportYScale();
-		float vpYCenter = gstate.getViewportY2();
+		float vpYCenter = gstate.getViewportYCenter();
 
 		// The viewport transform appears to go like this:
 		// Xscreen = -offsetX + vpXCenter + vpXScale * Xview
@@ -871,8 +871,8 @@ void TransformDrawEngine::ApplyDrawState(int prim) {
 
 		glstate.viewport.set(left, bottom, right - left, top - bottom);
 
-		float zScale = gstate.getViewportZ1() * (1.0f / 65535.0f);
+		float zScale = gstate.getViewportZScale() * (1.0f / 65535.0f);
-		float zCenter = gstate.getViewportZ2() * (1.0f / 65535.0f);
+		float zCenter = gstate.getViewportZCenter() * (1.0f / 65535.0f);
 		float depthRangeMin = zCenter - zScale;
 		float depthRangeMax = zCenter + zScale;
 		glstate.depthRange.set(depthRangeMin, depthRangeMax);

GPU/GPUState.h

@@ -89,12 +89,12 @@ struct GPUgstate {
 				texmtxnum,    // 0x40
 				texmtxdata,   // 0x41
 
-				viewportx1,           // 0x42
+				viewportxscale,           // 0x42
-				viewporty1,           // 0x43
+				viewportyscale,           // 0x43
-				viewportz1,           // 0x44
+				viewportzscale,           // 0x44
-				viewportx2,           // 0x45
+				viewportxcenter,           // 0x45
-				viewporty2,           // 0x46
+				viewportycenter,           // 0x46
-				viewportz2,           // 0x47
+				viewportzcenter,           // 0x47
 				texscaleu,            // 0x48
 				texscalev,            // 0x49
 				texoffsetu,           // 0x4A
@@ -375,16 +375,15 @@ struct GPUgstate {
 	int getRegionY2() const { return (region2 >> 10) & 0x3FF; }
 
 	// Note that the X1/Y1/Z1 here does not mean the upper-left corner, but half the dimensions. X2/Y2/Z2 are the center.
-	float getViewportX1() const { return getFloat24(viewportx1); }
+	float getViewportXScale() const { return getFloat24(viewportxscale); }
-	float getViewportY1() const { return getFloat24(viewporty1); }
+	float getViewportYScale() const { return getFloat24(viewportyscale); }
-	float getViewportZ1() const { return getFloat24(viewportz1); }
+	float getViewportZScale() const { return getFloat24(viewportzscale); }
-	float getViewportX2() const { return getFloat24(viewportx2); }
+	float getViewportXCenter() const { return getFloat24(viewportxcenter); }
-	float getViewportY2() const { return getFloat24(viewporty2); }
+	float getViewportYCenter() const { return getFloat24(viewportycenter); }
-	float getViewportZ2() const { return getFloat24(viewportz2); }
+	float getViewportZCenter() const { return getFloat24(viewportzcenter); }
 
 	// Fixed 16 point.
 	int getOffsetX16() const { return offsetx & 0xFFFF; }
-	// Fixed 16 point.
 	int getOffsetY16() const { return offsety & 0xFFFF; }
 	float getOffsetX() const { return (float)getOffsetX16() / 16.0f; }
 	float getOffsetY() const { return (float)getOffsetY16() / 16.0f; }

GPU/Software/TransformUnit.cpp

@@ -61,30 +61,30 @@ static inline ScreenCoords ClipToScreenInternal(const ClipCoords& coords, bool *
 	// Parameters here can seem invalid, but the PSP is fine with negative viewport widths etc.
 	// The checking that OpenGL and D3D do is actually quite superflous as the calculations still "work"
 	// with some pretty crazy inputs, which PSP games are happy to do at times.
-	float vpx1 = gstate.getViewportX1();
+	float xScale = gstate.getViewportXScale();
-	float vpx2 = gstate.getViewportX2();
+	float xCenter = gstate.getViewportXCenter();
-	float vpy1 = gstate.getViewportY1();
+	float yScale = gstate.getViewportYScale();
-	float vpy2 = gstate.getViewportY2();
+	float yCenter = gstate.getViewportYCenter();
-	float vpz1 = gstate.getViewportZ1();
+	float zScale = gstate.getViewportZScale();
-	float vpz2 = gstate.getViewportZ2();
+	float zCenter = gstate.getViewportZCenter();
 
-	float retx = coords.x * vpx1 / coords.w + vpx2;
+	float x = coords.x * xScale / coords.w + xCenter;
-	float rety = coords.y * vpy1 / coords.w + vpy2;
+	float y = coords.y * yScale / coords.w + yCenter;
-	float retz = coords.z * vpz1 / coords.w + vpz2;
+	float z = coords.z * zScale / coords.w + zCenter;
 
 	// Is this really right?
 	if (gstate.clipEnable & 0x1) {
-		if (retz < 0.f)
+		if (z < 0.f)
-			retz = 0.f;
+			z = 0.f;
-		if (retz > 65535.f)
+		if (z > 65535.f)
-			retz = 65535.f;
+			z = 65535.f;
 	}
 
-	if (outside_range_flag && (retx > 4095.9375f || rety > 4095.9375f || retx < 0 || rety < 0 || retz < 0 || retz > 65535.f))
+	if (outside_range_flag && (x > 4095.9375f || y > 4095.9375f || x < 0 || y < 0 || z < 0 || z > 65535.f))
 		*outside_range_flag = true;
 
 	// 16 = 0xFFFF / 4095.9375
-	return ScreenCoords(retx * 16, rety * 16, retz);
+	return ScreenCoords(x * 16, y * 16, z);
 }
 
 ScreenCoords TransformUnit::ClipToScreen(const ClipCoords& coords)