Added texture offsets. Vertex shader has been updated in Shaders/Vertex.glsl.

Added palette initialization to 2D renderer. Fixes 2D graphics corruption when loading states (most visible in Scud Race).

Src/Graphics/Render2D.cpp

@@ -737,11 +737,27 @@ void CRender2D::EndFrame(void)
  Emulation Callbacks
 ******************************************************************************/
 
-void CRender2D::WriteVRAM(unsigned addr, UINT32 data)
+void CRender2D::WritePalette(unsigned color, UINT32 data)
 {
-	unsigned	color;
 	UINT8		r, g, b, a;
 	
+	a = 0xFF * ((data>>15)&1); 	// decode the RGBA (make alpha 0xFF or 0x00)
+    a = ~a;                  	// invert it (set on Model 3 means clear pixel)
+	
+	if ((data&0x8000))
+    	r = g = b = 0;
+	else
+    {
+    	b = (data>>7)&0xF8;
+        g = (data>>2)&0xF8;
+        r = (data<<3)&0xF8;
+	}
+	
+	pal[color] = (a<<24)|(b<<16)|(g<<8)|r;
+}
+
+void CRender2D::WriteVRAM(unsigned addr, UINT32 data)
+{
 	if (vram[addr/4] == data)	// do nothing if no changes
 		return;
 		
@@ -751,19 +767,27 @@ void CRender2D::WriteVRAM(unsigned addr, UINT32 data)
 	// Palette
 	if (addr >= 0x100000)
     {
-        color = (addr-0x100000)/4;	// color index
+		unsigned color = (addr-0x100000)/4;	// color index
-        a = 0xFF * ((data>>15)&1); 	// decode the RGBA (make alpha 0xFF or 0x00)
+        WritePalette(color, data);
-        a = ~a;                  	// invert it (set on Model 3 means clear pixel)
+    }
-        if ((data&0x8000))
+}
-        	r = g = b = 0;
+
-        else
+/*
+ * InitPalette():
+ *
+ * This must be called from AttachVRAM() to initialize the palette. The reason 
+ * is that because WriteVRAM() always compares incoming data to what is already
+ * in the VRAM, there is no actual way to initialize the palette by calling
+ * WriteVRAM() and passing it the initial VRAM contents. It will always fail to
+ * update because nothing is being changed.
+ *
+ * This function fixes the transparent pixel bug that frequently occurred when
+ * loading save states in Supermodel 0.1a.
+ */
+void CRender2D::InitPalette(void)
 {
-        	b = (data>>7)&0xF8;
+	for (int i = 0; i < 0x20000/4; i++)
-        	g = (data>>2)&0xF8;
+		WritePalette(i, vram[0x100000/4 + i]);
-        	r = (data<<3)&0xF8;
-        }
-        pal[color] = (a<<24)|(b<<16)|(g<<8)|r;
-    }
 }
 
 
@@ -780,6 +804,7 @@ void CRender2D::AttachRegisters(const UINT32 *regPtr)
 void CRender2D::AttachVRAM(const UINT8 *vramPtr)
 {
 	vram = (UINT32 *) vramPtr;
+	InitPalette();
 	DebugLog("Render2D attached VRAM\n");
 }
 

Src/Graphics/Render2D.h

@@ -145,6 +145,8 @@ private:
 	void DisplayLayer(int layerNum, GLfloat z);
 	void Setup2D(void);
 	void ColorOffset(GLfloat colorOffset[3], UINT32 reg);
+	void WritePalette(unsigned color, UINT32 data);
+	void InitPalette(void);
 		
 	// Data received from tile generator device object
 	const UINT32	*vram;

Src/Graphics/Render3D.cpp

@@ -188,6 +188,9 @@ void CRender3D::DecodeTexture(int format, int x, int y, int width, int height)
 	UINT16	texel;
 	GLfloat	c, a;
 	
+	x %= 2048;
+	y %= 2048;
+	
 	if ((x+width)>2048 || (y+height)>2048)
 		return;
 	if (width > 512 || height > 512)
@@ -662,7 +665,8 @@ void CRender3D::DescendCullingNode(UINT32 addr)
 {
 	const UINT32	*node, *lodTable;
 	UINT32			matrixOffset, node1Ptr, node2Ptr;
-	float			x, y, z;
+	float			x, y, z, oldTexOffsetX, oldTexOffsetY;
+	int				tx, ty;
 	
 	++stackDepth;
 	// Stack depth of 64 is too small for Star Wars Trilogy (Hoth)
@@ -691,6 +695,18 @@ void CRender3D::DescendCullingNode(UINT32 addr)
 	y				= *(float *) &node[0x05-offset];
 	z				= *(float *) &node[0x06-offset];
 	
+	// Texture offset?
+	oldTexOffsetX = texOffset[0];	// save old offsets
+	oldTexOffsetY = texOffset[1];
+	tx = 32*((node[0x02]>>7)&0x3F);
+	ty = 32*(node[0x02]&0x3F) + ((node[0x02]&0x4000)?1024:0);
+	if ((node[0x02]&0x8000))	// apply texture offsets, else retain current ones
+	{
+		texOffset[0] = (GLfloat) tx;
+		texOffset[1] = (GLfloat) ty;
+		//printf("Tex Offset: %d, %d (%08X %08X)\n", tx, ty, node[0x02], node[0x00]);
+	}
+	
 	// Apply matrix and translation
 	glPushMatrix();
 	if ((node[0x00]&0x10))	// apply translation vector
@@ -717,6 +733,10 @@ void CRender3D::DescendCullingNode(UINT32 addr)
 	glPopMatrix();
 	DescendNodePtr(node2Ptr);
 	--stackDepth;
+	
+	// Restore old texture offsets
+	texOffset[0] = oldTexOffsetX;
+	texOffset[1] = oldTexOffsetY;
 }
 
 // A list of pointers. MAME assumes that these may only point to culling nodes.
@@ -1098,6 +1118,10 @@ void CRender3D::RenderViewport(UINT32 addr, int pri)
 	//printf("scrollFog = %g, scrollAtt = %g\n", scrollFog, scrollAtt);
 	//printf("Fog: R=%02X G=%02X B=%02X density=%g (%X) %d start=%g\n", ((vpnode[0x22]>>16)&0xFF), ((vpnode[0x22]>>8)&0xFF), ((vpnode[0x22]>>0)&0xFF), fogParams[3], vpnode[0x23], (fogParams[3]==fogParams[3]), fogParams[4]);
  	
+ 	// Clear texture offsets before proceeding
+ 	texOffset[0] = 0.0;
+ 	texOffset[1] = 0.0;
+ 	
  	// Set up coordinate system and base matrix
  	glMatrixMode(GL_MODELVIEW);
  	InitMatrixStack(matrixBase);
@@ -1305,6 +1329,7 @@ BOOL CRender3D::Init(unsigned xOffset, unsigned yOffset, unsigned xRes, unsigned
 	spotEllipseLoc = glGetUniformLocation(shaderProgram, "spotEllipse");
 	spotRangeLoc = glGetUniformLocation(shaderProgram, "spotRange");
 	spotColorLoc = glGetUniformLocation(shaderProgram, "spotColor");
+	texOffsetLoc = glGetUniformLocation(shaderProgram, "texOffset");
 	
 	// Get locations of custom vertex attributes
 	subTextureLoc = glGetAttribLocation(shaderProgram,"subTexture");

Src/Graphics/Render3D.h

@@ -92,6 +92,7 @@ struct DisplayList
 		struct
 		{
 			GLfloat		modelViewMatrix[4*4];	// model-view matrix
+			GLfloat		texOffset[2];			// texture offset (X, Y)
 			unsigned	index;					// index in VBO
 			unsigned	numVerts;				// number of vertices
 		} Model;
@@ -357,6 +358,9 @@ private:
 	int		listDepth;	// how many lists have we recursed into
 	int		stackDepth;	// for debugging and error handling purposes
 	
+	// Texture offset (during scene graph processing)
+	GLfloat	texOffset[2];	// X, Y
+	
 	// Resolution scaling factors (to support resolutions higher than 496x384) and offsets
 	GLfloat		xRatio, yRatio;
 	unsigned	xOffs, yOffs;
@@ -375,6 +379,7 @@ private:
 	GLuint	spotEllipseLoc;			// uniform
 	GLuint	spotRangeLoc;			// uniform
 	GLuint	spotColorLoc;			// uniform
+	GLuint	texOffsetLoc;			// uniform
 	GLuint	subTextureLoc;			// attribute
 	GLuint	texParamsLoc;			// attribute
 	GLuint	texFormatLoc;			// attribute

Src/Graphics/Shaders/Vertex.glsl

@@ -34,6 +34,7 @@ uniform vec3	lighting[2];		// lighting state (lighting[0] = sun direction, light
 uniform vec4	spotEllipse;		// spotlight ellipse position: .x=X position (normalized device coordinates), .y=Y position, .z=half-width, .w=half-height)
 uniform vec2	spotRange;			// spotlight Z range: .x=start (viewspace coordinates), .y=limit
 uniform vec3	spotColor;			// spotlight RGB color
+uniform vec2	texOffset;			// offset (within 2048x2048 texture sheet) to apply to texture base coordinates
 
 // Custom vertex attributes
 attribute vec4	subTexture;		// .x=texture X, .y=texture Y, .z=texture width, .w=texture height (all in texels)
@@ -138,6 +139,7 @@ void main(void)
 	// Pass remaining parameters to fragment shader
 	gl_TexCoord[0] = gl_MultiTexCoord0;
 	fsSubTexture = subTexture;
+	fsSubTexture.xy += texOffset;	// apply texture offset
 	fsTexParams = texParams;
 	fsTransLevel = transLevel;
 	fsTexFormat = texFormat;