Texture conversion and loading

1 files changed, 217 insertions, 0 deletions

diff --git a/convtexture.c b/convtexture.c
new file mode 100644
index 0000000..a04e3c9
--- /dev/null
+++ b/convtexture.c
@@ -0,0 +1,217 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "plat.h"
+#include "str.h"
+#include "vid_enums.h"
+
+typedef struct {
+	float r, g, b;
+} vec3;
+
+typedef struct {
+	unsigned char r, g, b, a;
+} Colour;
+
+typedef struct {
+	Colour* pixels;
+	int w, h;
+} Image;
+
+typedef struct {
+	vec3 start, end;
+	unsigned char indices[4 * 4];
+} Block;
+
+const char* format_names[] = {
+#define x(n) #n,
+	texture_format_xmacro()
+#undef x
+};
+
+void get_block(Block* block, Colour* pixels, int stride) {
+	int x, y, i;
+	vec3 cols[4 * 4];
+	vec3 s, e;
+	float cd;
+	for (y = 0; y < 4; y++) {
+		for (x = 0; x < 4; x++) {
+			Colour pixel = pixels[x + y * stride];
+			vec3 vec;
+			vec.r = (float)pixel.r / 255.0f;
+			vec.g = (float)pixel.g / 255.0f;
+			vec.b = (float)pixel.b / 255.0f;
+			cols[x + y * 4] = vec;
+		}
+	}
+	cd = -1.0f;
+	for (i = 0; i < 4 * 4; i++) {
+		int j;
+		vec3* a = &cols[i];
+		for (j = i + 1; j < 4 * 4; j++) {
+			vec3* b = &cols[j];
+			float d =
+				(b->r - a->r) * (b->r - a->r) +
+				(b->g - a->g) * (b->g - a->g) +
+				(b->b - a->b) * (b->b - a->b);
+			if (d > cd) {
+				cd = d;
+				s = *a;
+				e = *b;
+			}
+		}
+	}
+	for (i = 0; i < 4 * 4; i++) {
+		vec3* col = &cols[i];
+		float d;
+		d =
+			(e.r - col->r) * (e.r - col->r) +
+			(e.g - col->g) * (e.g - col->g) +
+			(e.b - col->b) * (e.b - col->b);
+		if (cd < 0.0001f)
+			block->indices[i] = 0;
+		else {
+			d = d / cd;
+			block->indices[i] = (int)((1.0f - d) * 3.1f);
+		}
+	}
+	block->start = s;
+	block->end = e;
+}
+
+void compress_block(const Block* block, FILE* f) {
+	int i;
+	unsigned start =
+		((unsigned)(block->start.r * 31.9999f) << 11) |
+		((unsigned)(block->start.g * 63.9999f) << 5) |
+		((unsigned)(block->start.b * 31.9999f));
+	unsigned end =
+		((unsigned)(block->end.r * 31.9999f) << 11) |
+		((unsigned)(block->end.g * 63.9999f) << 5) |
+		((unsigned)(block->end.b * 31.9999f));
+	unsigned palette = (start << 16) | end;
+	unsigned indices = 0;
+	fwrite(&palette, 1, 4, f);
+	for (i = 0; i < 4 * 4; i++) {
+		indices |= block->indices[i] << (i * 2);
+	}
+	fwrite(&indices, 1, 4, f);
+}
+
+void compress_bc1(Colour* pixels, int w, int h, FILE* f) {
+	int x, y, cw, ch;
+	Block block;
+	cw = w / 4;
+	ch = h / 4;
+	for (y = 0; y < ch; y++) {
+		for (x = 0; x < cw; x++) {
+			get_block(&block, &pixels[x * 4 + y * 4 * w], w);
+			compress_block(&block, f);
+		}
+	}
+}
+
+void convert(Image* image, Texture_Format target, FILE* f) {
+	fwrite("TXTR", 1, 4, f);
+	fwrite(&image->w, 1, 4, f);
+	fwrite(&image->h, 1, 4, f);
+	fwrite(&target, 1, 4, f);
+	switch (target) {
+		case texture_format_bc1:
+			compress_bc1(image->pixels, image->w, image->h, f);
+			break;
+		default:
+			print_err("Unsupported target format.\n");
+			pbreak(40);
+	}
+}
+
+Texture_Format texture_format_from_string(const char* s) {
+	int i, e = sizeof format_names / sizeof *format_names;
+	for (i = 0; i < e; i++)
+		if (string_equal(s, format_names[i]))
+			return (Texture_Format)i;
+	print_err("Invalid texture format %s\n", s);
+	pbreak(10);
+	return (Texture_Format)0;
+}
+
+int main(int argc, const char** argv) {
+	FILE* outfile, * infile;
+	char bmp_magic[2];
+	unsigned bmp_offset;
+	int bmp_w, bmp_h, s, x, y;
+	unsigned short bmp_bits;
+	Colour* buffer;
+	Image img;
+	Colour pixel;
+	Texture_Format target;
+
+	if (argc < 4) {
+		print_err("Usage: %s infile outfile format.\n", argv[0]);
+		return 1;
+	}
+
+	infile = fopen(argv[1], "rb");
+	if (!infile) {
+		print_err("Failed to open %s.\n", argv[1]);
+		return 2;
+	}
+	target = texture_format_from_string(argv[3]);
+
+	fread(bmp_magic, 2, 1, infile);
+	if (bmp_magic[0] != 'B' || bmp_magic[1] != 'M') {
+		print_err("Not a valid bitmap file.\n");
+		return 3;
+	}
+
+	fseek(infile, 10, SEEK_SET);
+	fread(&bmp_offset, 4, 1, infile);
+	fseek(infile, 18, SEEK_SET);
+	fread(&bmp_w,    4, 1, infile);
+	fread(&bmp_h,    4, 1, infile);
+	fseek(infile, 28, SEEK_SET);
+	fread(&bmp_bits, 2, 1, infile);
+
+	if (bmp_bits != 32) {
+		print_err("Bitmap must have 32 bit pixels. Instead has %d bit pixels.\n", bmp_bits);
+		return 4;
+	}
+
+	if (bmp_w % 4 != 0 || bmp_h % 4 != 0) {
+		print_err("Bitmap must have a size divisible by four.\n");
+		return 5;
+	}
+
+	fseek(infile, bmp_offset, SEEK_SET);
+	s = bmp_w * bmp_h;
+	buffer = malloc(s * 4);
+	/* Flip & read. */
+	for (y = 0; y < bmp_h; y++) {
+		for (x = 0; x < bmp_w; x++) {
+			unsigned char t;
+			fread(&pixel, 1, 4, infile);
+			t = pixel.r;
+			pixel.r = pixel.b;
+			pixel.b = t;
+			if (pixel.a == 0) {
+				pixel.r = 0;
+				pixel.g = 0;
+				pixel.b = 0;
+			}
+			buffer[x + (bmp_h - y - 1) * bmp_w] = pixel;
+		}
+	}
+	outfile = fopen(argv[2], "wb");
+	if (!outfile) {
+		print_err("Failed to open %s.\n", argv[2]);
+		return 6;
+	}
+	img.pixels = buffer;
+	img.w = bmp_w;
+	img.h = bmp_h;
+	convert(&img, target, outfile);
+	fclose(outfile);
+	return 0;
+}
+