Choose better alignment for heavy-duty rendering structures, patch by Matt Turner (#4981)

code/qcommon/q_shared.h

@@ -183,8 +183,10 @@ typedef int		sfxHandle_t;
 typedef int		fileHandle_t;
 typedef int		clipHandle_t;
 
-#define PAD(x,y)	(((x)+(y)-1) & ~((y)-1))
-#define PADLEN(x,y)	(PAD((x), (y)) - (x))
+#define PAD(base, alignment)	(((base)+(alignment)-1) & ~((alignment)-1))
+#define PADLEN(base, alignment)	(PAD((base), (alignment)) - (base))
+
+#define PADP(base, alignment)	((void *) PAD((intptr_t) (base), (alignment)))
 
 #ifdef __GNUC__
 #define QALIGN(x) __attribute__((aligned(x)))

code/renderer/tr_backend.c

@@ -1142,6 +1142,8 @@ void RB_ExecuteRenderCommands( const void *data ) {
 	}
 
 	while ( 1 ) {
+		data = PADP(data, sizeof(void *));
+
 		switch ( *(const int *)data ) {
 		case RC_SET_COLOR:
 			data = RB_SetColor( data );

code/renderer/tr_cmds.c

@@ -195,6 +195,7 @@ void *R_GetCommandBuffer( int bytes ) {
 	renderCommandList_t	*cmdList;
 
 	cmdList = &backEndData[tr.smpFrame]->commands;
+	bytes = PAD(bytes, sizeof(void *));
 
 	// always leave room for the end of list command
 	if ( cmdList->used + bytes + 4 > MAX_RENDER_COMMANDS ) {

code/renderer/tr_init.c

@@ -382,7 +382,7 @@ byte *RB_ReadPixels(int x, int y, int width, int height, size_t *offset, int *pa
 	// Allocate a few more bytes so that we can choose an alignment we like
 	buffer = ri.Hunk_AllocateTempMemory(padwidth * height + *offset + packAlign - 1);
 	
-	bufstart = (byte *) PAD((intptr_t) buffer + *offset, packAlign);
+	bufstart = PADP((intptr_t) buffer + *offset, packAlign);
 	qglReadPixels(x, y, width, height, GL_RGB, GL_UNSIGNED_BYTE, bufstart);
 	
 	*offset = bufstart - buffer;
@@ -780,7 +780,7 @@ const void *RB_TakeVideoFrameCmd( const void *data )
 	avipadwidth = PAD(linelen, AVI_LINE_PADDING);
 	avipadlen = avipadwidth - linelen;
 
-	cBuf = (byte *) PAD((intptr_t) cmd->captureBuffer, packAlign);
+	cBuf = PADP(cmd->captureBuffer, packAlign);
 		
 	qglReadPixels(0, 0, cmd->width, cmd->height, GL_RGB,
 		GL_UNSIGNED_BYTE, cBuf);

code/renderer/tr_shader.c

@@ -1878,6 +1878,8 @@ static void FixRenderCommandList( int newShader ) {
 		const void *curCmd = cmdList->cmds;
 
 		while ( 1 ) {
+			curCmd = PADP(curCmd, sizeof(void *));
+
 			switch ( *(const int *)curCmd ) {
 			case RC_SET_COLOR:
 				{