add support for loading PVR images

this is from Q3A for Dreamcast

cmake/renderer_common.cmake

@@ -6,6 +6,7 @@ set(RENDERER_COMMON_SOURCES
     ${SOURCE_DIR}/renderercommon/tr_image_jpg.c
     ${SOURCE_DIR}/renderercommon/tr_image_pcx.c
     ${SOURCE_DIR}/renderercommon/tr_image_png.c
+    ${SOURCE_DIR}/renderercommon/tr_image_pvr.c
     ${SOURCE_DIR}/renderercommon/tr_image_tga.c
     ${SOURCE_DIR}/renderercommon/tr_noise.c
     ${SOURCE_DIR}/renderercommon/puff.c

code/renderercommon/tr_common.h

@@ -146,6 +146,7 @@ void R_LoadBMP( const char *name, byte **pic, int *width, int *height );
 void R_LoadJPG( const char *name, byte **pic, int *width, int *height );
 void R_LoadPCX( const char *name, byte **pic, int *width, int *height );
 void R_LoadPNG( const char *name, byte **pic, int *width, int *height );
+void R_LoadPVR( const char *name, byte **pic, int *width, int *height );
 void R_LoadTGA( const char *name, byte **pic, int *width, int *height );
 
 /*

code/renderercommon/tr_image_pvr.c

@@ -0,0 +1,164 @@
+/*
+===========================================================================
+Copyright (C) 1999-2005 Id Software, Inc.
+
+This file is part of Quake III Arena source code.
+
+Quake III Arena source code is free software; you can redistribute it
+and/or modify it under the terms of the GNU General Public License as
+published by the Free Software Foundation; either version 2 of the License,
+or (at your option) any later version.
+
+Quake III Arena source code is distributed in the hope that it will be
+useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Quake III Arena source code; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+===========================================================================
+*/
+
+#include "tr_common.h"
+
+typedef struct pvr {
+	unsigned char magic[4];
+	unsigned int len_file;
+	unsigned int type;
+	unsigned short width;
+	unsigned short height;
+	unsigned short codebook[1024];
+	unsigned char indices[1];
+} pvr_t;
+
+static int log2approx(int x)
+{
+	switch (x)
+	{
+		case 8: return 3;
+		case 16: return 4;
+		case 32: return 5;
+		case 64: return 6;
+		case 128: return 7;
+		case 256: return 8;
+		case 512: return 9;
+		case 1024: return 10;
+		default: return -1;
+	}
+}
+
+static int from_xy(int x, int y, int w, int h)
+{
+	int wmax, hmax;
+	int i, idx = 0;
+
+	wmax = log2approx(w);
+	hmax = log2approx(h);
+
+	if (wmax < 0 || hmax < 0)
+		return -1;
+
+	for (i = 0; i < 10; i++)
+	{
+		if (i < wmax && i < hmax)
+		{
+			idx |= ((y >> i) & 1) << (i * 2 + 0);
+			idx |= ((x >> i) & 1) << (i * 2 + 1);
+		}
+		else if (i < wmax)
+		{
+			idx |= ((x >> i) & 1) << (i + hmax);
+		}
+		else if (i < hmax)
+		{
+			idx |= ((y >> i) & 1) << (i + wmax);
+		}
+		else
+		{
+			break;
+		}
+	}
+
+	return idx;
+}
+
+static unsigned int rgb565_to_rgba24(unsigned short color)
+{
+	unsigned char r, g, b, a;
+	r = ((color >> 11) & 31) << 3;
+	g = ((color >> 5) & 63) << 2;
+	b = ((color >> 0) & 31) << 3;
+	a = 255;
+	return (a << 24) | (b << 16) | (g << 8) | r;
+}
+
+void R_LoadPVR(const char *name, byte **pic, int *width, int *height)
+{
+	unsigned int length;
+	void *buffer;
+	pvr_t *pvr;
+	unsigned int *rgba;
+	int x, y;
+
+	*pic = NULL;
+	if (width)
+		*width = 0;
+	if (height)
+		*height = 0;
+
+	// load the file
+	length = ri.FS_ReadFile((char *)name, &buffer);
+	if (!buffer || length < 0)
+		return;
+
+	// check magic identifier
+	pvr = (pvr_t *)buffer;
+	if (memcmp(pvr->magic, "PVRT", sizeof(pvr->magic)) != 0)
+		ri.Error(ERR_DROP, "LoadPVR: magic identifier does not match expected (%s)", name);
+
+	// fix up header
+	pvr->len_file = LittleLong(pvr->len_file);
+	pvr->type = LittleLong(pvr->type);
+	pvr->width = LittleShort(pvr->width);
+	pvr->height = LittleShort(pvr->height);
+
+	// allocate rgba buffer
+	rgba = (unsigned int *)ri.Malloc(pvr->width * pvr->height * 4);
+
+	// decompress image
+	for (y = 0; y < pvr->height / 2; y++)
+	{
+		for (x = 0; x < pvr->width / 2; x++)
+		{
+			unsigned short *colors;
+			int a, b, c, d;
+			int idx = from_xy(x, y, pvr->width, pvr->height);
+
+			if (idx < 0)
+				ri.Error(ERR_DROP, "LoadPVR: invalid data passed to decompressor (%s)", name);
+
+			colors = &pvr->codebook[pvr->indices[idx] * 4];
+
+			a = ((y * 2) + 0) * pvr->width + ((x * 2) + 0);
+			b = ((y * 2) + 1) * pvr->width + ((x * 2) + 0);
+			c = ((y * 2) + 0) * pvr->width + ((x * 2) + 1);
+			d = ((y * 2) + 1) * pvr->width + ((x * 2) + 1);
+
+			rgba[a] = rgb565_to_rgba24(colors[0]);
+			rgba[b] = rgb565_to_rgba24(colors[1]);
+			rgba[c] = rgb565_to_rgba24(colors[2]);
+			rgba[d] = rgb565_to_rgba24(colors[3]);
+		}
+	}
+
+	// clean up
+	ri.FS_FreeFile(buffer);
+
+	// return stuff
+	*pic = (byte *)rgba;
+	if (width)
+		*width = pvr->width;
+	if (height)
+		*height = pvr->height;
+}

code/renderergl1/tr_image.c

@@ -926,7 +926,8 @@ static imageExtToLoaderMap_t imageLoaders[ ] =
 	{ "jpeg", R_LoadJPG },
 	{ "png",  R_LoadPNG },
 	{ "pcx",  R_LoadPCX },
-	{ "bmp",  R_LoadBMP }
+	{ "bmp",  R_LoadBMP },
+	{ "pvr",  R_LoadPVR }
 };
 
 static int numImageLoaders = ARRAY_LEN( imageLoaders );

code/renderergl2/tr_image.c

@@ -2392,7 +2392,8 @@ static imageExtToLoaderMap_t imageLoaders[ ] =
 	{ "jpg",  R_LoadJPG },
 	{ "jpeg", R_LoadJPG },
 	{ "pcx",  R_LoadPCX },
-	{ "bmp",  R_LoadBMP }
+	{ "bmp",  R_LoadBMP },
+	{ "pvr",  R_LoadPVR }
 };
 
 static int numImageLoaders = ARRAY_LEN( imageLoaders );