From 4000d858aed75d56961a40be2dfd313b1a32a41b Mon Sep 17 00:00:00 2001
From: Eleni Maria Stea <estea@igalia.com>
Date: Tue, 13 Mar 2018 09:59:55 +0200
Subject: [PATCH] This is a test program that loads compressed data, renders
 the image and gets the pixels with glGetCompressedTexImage*
 functions.

Just for testing.
---
 Makefile           |   12 ++
 README             |    8 ++
 compressed_texture |  Bin 0 -> 131080 bytes
 main.c             |  359 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 379 insertions(+)
 create mode 100644 Makefile
 create mode 100644 README
 create mode 100644 compressed_texture
 create mode 100644 main.c

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..84363ff
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,12 @@
+obj = main.o
+bin = test
+
+CFLAGS = -pedantic -Wall -g
+LDFLAGS = -lGL -lglut
+
+$(bin): $(obj)
+	$(CC) -o $@ $(obj) $(LDFLAGS)
+
+.PHONY: clean
+clean:
+	rm -f $(obj) $(bin)
diff --git a/README b/README
new file mode 100644
index 0000000..6a8352c
--- /dev/null
+++ b/README
@@ -0,0 +1,8 @@
+Build and Run:
+--------------
+Build:
+make
+
+Run:
+./test if your gpu can compress textures
+./test compressed_texture to load already compressed data (recommended)
diff --git a/compressed_texture b/compressed_texture
new file mode 100644
index 0000000000000000000000000000000000000000..af66f3a2a004622b7786575996989ee3380eca7a
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diff --git a/main.c b/main.c
new file mode 100644
index 0000000..32da284
--- /dev/null
+++ b/main.c
@@ -0,0 +1,359 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <GL/freeglut.h>
+
+#undef USE_SRGB
+
+#ifdef USE_SRGB
+#define COMP_FMT	GL_COMPRESSED_SRGB8_ETC2
+#else
+#define COMP_FMT	GL_COMPRESSED_RGB8_ETC2
+#endif
+
+int init(void);
+int texcomp(unsigned char *compix, unsigned int tofmt, unsigned char *pixels,
+		int xsz, int ysz, unsigned int fromfmt, unsigned int fromtype);
+void disp(void);
+void reshape(int x, int y);
+void keyb(unsigned char key, int x, int y);
+void gen_image(unsigned char *pixels, int xsz, int ysz);
+unsigned char *load_compressed_image(const char *fname, int *cszptr, int *xszptr, int *yszptr);
+int dump_compressed_image(const char *fname, unsigned char *data, int size, int w, int h);
+void print_compressed_formats(void);
+
+unsigned int tex, comp_tex;
+const char *texfile;
+
+int main(int argc, char **argv)
+{
+	unsigned int glut_flags = GLUT_RGB | GLUT_DOUBLE;
+#ifdef USE_SRGB
+	glut_flags |= GLUT_SRGB;
+#endif
+
+	texfile = argv[1];
+
+	glutInit(&argc, argv);
+	glutInitWindowSize(800, 600);
+	glutInitDisplayMode(glut_flags);
+	glutCreateWindow("test");
+
+	glutDisplayFunc(disp);
+	glutReshapeFunc(reshape);
+	glutKeyboardFunc(keyb);
+
+	if(init() == -1) {
+		return 1;
+	}
+
+	glutMainLoop();
+	return 0;
+}
+
+int init(void)
+{
+	unsigned char *pixels, *buf;
+	int xsz = 512;
+	int ysz = 512;
+	int is_comp = 0;
+	int comp_size = 0;
+	int tmp;
+
+	print_compressed_formats();
+
+	if(texfile) {
+		if(!(pixels = load_compressed_image(texfile, &comp_size, &xsz, &ysz))) {
+			return -1;
+		}
+		printf("loaded compressed texture file: %s (%dx%d)\n", texfile, xsz, ysz);
+
+	} else {
+		if(!(pixels = malloc(xsz * ysz * 3))) {
+			abort();
+		}
+		gen_image(pixels, xsz, ysz);
+
+		printf("compressing texture\n");
+		if((comp_size = texcomp(pixels, COMP_FMT, pixels, xsz, ysz, GL_RGB, GL_UNSIGNED_BYTE)) == -1) {
+			return -1;
+		}
+		printf("compressed texture is %d bytes (uncompressed was: %d)\n", comp_size, xsz * ysz * 3);
+
+		dump_compressed_image("compressed_texture", pixels, comp_size, xsz, ysz);
+	}
+
+	glGenTextures(1, &tex);
+	glBindTexture(GL_TEXTURE_2D, tex);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glCompressedTexImage2D(GL_TEXTURE_2D, 0, COMP_FMT, xsz, ysz, 0, comp_size, pixels);
+	if(glGetError()) {
+		fprintf(stderr, "failed to upload compressed texture\n");
+		return -1;
+	}
+
+	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED, &is_comp);
+	if(!is_comp) {
+		fprintf(stderr, "texture is not compressed\n");
+		return -1;
+	}
+	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED_IMAGE_SIZE, &tmp);
+	if(tmp != comp_size) {
+		fprintf(stderr, "internal compressed size differs (expected: %d, got: %d)!\n", comp_size, tmp);
+		return -1;
+	}
+
+	if(!(buf = malloc(comp_size))) {
+		fprintf(stderr, "failed to allocate comparison image buffer (%d bytes)\n", comp_size);
+		return -1;
+	}
+	glGetCompressedTexImage(GL_TEXTURE_2D, 0, buf);
+
+	if(memcmp(pixels, buf, comp_size) != 0) {
+		fprintf(stderr, "submitted and retrieved pixel data differ!\n");
+	} else {
+		printf("submitted and retrieved sizes match (%d bytes)\n", comp_size);
+	}
+	free(buf);
+	free(pixels);
+
+#ifdef USE_SRGB
+	glEnable(GL_FRAMEBUFFER_SRGB);
+#endif
+
+	glEnable(GL_TEXTURE_2D);
+	return 0;
+}
+
+int texcomp(unsigned char *compix, unsigned int tofmt, unsigned char *pixels,
+		int xsz, int ysz, unsigned int fromfmt, unsigned int fromtype)
+{
+	unsigned int tex;
+	int is_comp = 0;
+	int comp_size = 0;
+
+	glGenTextures(1, &tex);
+	glBindTexture(GL_TEXTURE_2D, tex);
+	glTexImage2D(GL_TEXTURE_2D, 0, tofmt, xsz, ysz, 0, fromfmt, fromtype, pixels);
+	if(glGetError()) {
+		fprintf(stderr, "failed to compress texture\n");
+		return -1;
+	}
+
+	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED, &is_comp);
+	if(!is_comp) {
+		fprintf(stderr, "texture is not compressed\n");
+		return -1;
+	}
+	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED_IMAGE_SIZE, &comp_size);
+
+	glGetCompressedTexImage(GL_TEXTURE_2D, 0, compix);
+	return comp_size;
+}
+
+void disp(void)
+{
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	glBegin(GL_QUADS);
+	glTexCoord2f(0, 1); glVertex2f(-1, -1);
+	glTexCoord2f(1, 1); glVertex2f(1, -1);
+	glTexCoord2f(1, 0); glVertex2f(1, 1);
+	glTexCoord2f(0, 0);	glVertex2f(-1, 1);
+	glEnd();
+
+	glutSwapBuffers();
+	assert(glGetError() == GL_NO_ERROR);
+}
+
+void reshape(int x, int y)
+{
+	float aspect = (float)x / (float)y;
+	glViewport(0, 0, x, y);
+
+	glMatrixMode(GL_PROJECTION);
+	glLoadIdentity();
+	glScalef(1.0 / aspect, 1, 1);
+}
+
+void keyb(unsigned char key, int x, int y)
+{
+	if(key == 27) {
+		exit(0);
+	}
+}
+
+void gen_image(unsigned char *pixels, int xsz, int ysz)
+{
+	int i, j;
+
+	for(i=0; i<ysz; i++) {
+		for(j=0; j<xsz; j++) {
+			int xor = i ^ j;
+
+			*pixels++ = xor & 0xff;
+			*pixels++ = (xor << 1) & 0xff;
+			*pixels++ = (xor << 2) & 0xff;
+		}
+	}
+}
+
+unsigned char *load_compressed_image(const char *fname, int *cszptr, int *xszptr, int *yszptr)
+{
+	unsigned char *pixels;
+	long start, comp_size;
+	int xsz, ysz;
+	FILE *fp;
+
+	if(!(fp = fopen(texfile, "rb"))) {
+		fprintf(stderr, "failed to open compressed texture file: %s: %s\n", texfile, strerror(errno));
+		return 0;
+	}
+
+	if(fread(&xsz, sizeof xsz, 1, fp) < 1 || fread(&ysz, sizeof ysz, 1, fp) < 1) {
+		fprintf(stderr, "failed to read compressed texture file header: %s: %s\n", texfile, strerror(errno));
+		fclose(fp);
+		return 0;
+	}
+	start = ftell(fp);
+	fseek(fp, 0, SEEK_END);
+	comp_size = ftell(fp) - start;
+	fseek(fp, start, SEEK_SET);
+
+	if(!(pixels = malloc(comp_size))) {
+		perror("failed to allocate pixel buffer");
+		return 0;
+	}
+	if(fread(pixels, 1, comp_size, fp) < comp_size) {
+		fprintf(stderr, "failed to read compressed texture file: %s: %s\n", texfile, strerror(errno));
+		fclose(fp);
+		free(pixels);
+		return 0;
+	}
+	fclose(fp);
+
+	*cszptr = comp_size;
+	*xszptr = xsz;
+	*yszptr = ysz;
+	return pixels;
+}
+
+int dump_compressed_image(const char *fname, unsigned char *data, int size, int w, int h)
+{
+	FILE *fp;
+
+	if(!(fp = fopen(fname, "wb"))) {
+		fprintf(stderr, "failed to open compressed texture dump file: %s: %s\n", fname, strerror(errno));
+		return -1;
+	}
+
+	if(fwrite(&w, sizeof w, 1, fp) < 1 ||
+			fwrite(&h, sizeof h, 1, fp) < 1 ||
+			fwrite(data, 1, size, fp) < size) {
+		fprintf(stderr, "failed to dump compressed texture: %s\n", strerror(errno));
+	}
+	fclose(fp);
+	return 0;
+}
+
+const char *fmtstr(int fmt)
+{
+	switch(fmt) {
+	case 0x86b0: return "GL_COMPRESSED_RGB_FXT1_3DFX";
+	case 0x86b1: return "GL_COMPRESSED_RGBA_FXT1_3DFX";
+	case 0x8dbb: return "GL_COMPRESSED_RED_RGTC1";
+	case 0x8dbc: return "GL_COMPRESSED_SIGNED_RED_RGTC1";
+	case 0x8dbd: return "GL_COMPRESSED_RG_RGTC2";
+	case 0x8dbe: return "GL_COMPRESSED_SIGNED_RG_RGTC2";
+	case 0x8e8c: return "GL_COMPRESSED_RGBA_BPTC_UNORM";
+	case 0x8e8d: return "GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM";
+	case 0x8e8e: return "GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT";
+	case 0x8e8f: return "GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT";
+	case 0x9274: return "GL_COMPRESSED_RGB8_ETC2";
+	case 0x9275: return "GL_COMPRESSED_SRGB8_ETC2";
+	case 0x9276: return "GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2";
+	case 0x9277: return "GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2";
+	case 0x9278: return "GL_COMPRESSED_RGBA8_ETC2_EAC";
+	case 0x9279: return "GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC";
+	case 0x9270: return "GL_COMPRESSED_R11_EAC";
+	case 0x9271: return "GL_COMPRESSED_SIGNED_R11_EAC";
+	case 0x9272: return "GL_COMPRESSED_RG11_EAC";
+	case 0x9273: return "GL_COMPRESSED_SIGNED_RG11_EAC";
+	case 0x83F0: return "GL_COMPRESSED_RGB_S3TC_DXT1_EXT";
+	case 0x83F1: return "GL_COMPRESSED_RGBA_S3TC_DXT1_EXT";
+	case 0x83F2: return "GL_COMPRESSED_RGBA_S3TC_DXT3_EXT";
+	case 0x83F3: return "GL_COMPRESSED_RGBA_S3TC_DXT5_EXT";
+	case 0x8C48: return "GL_COMPRESSED_SRGB_EXT";
+	case 0x8C49: return "GL_COMPRESSED_SRGB_ALPHA_EXT";
+	case 0x8C4A: return "GL_COMPRESSED_SLUMINANCE_EXT";
+	case 0x8C4B: return "GL_COMPRESSED_SLUMINANCE_ALPHA_EXT";
+	case 0x8C4C: return "GL_COMPRESSED_SRGB_S3TC_DXT1_EXT";
+	case 0x8C4D: return "GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT";
+	case 0x8C4E: return "GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT";
+	case 0x8C4F: return "GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT";
+	case 0x8B90: return "GL_PALETTE4_RGB8_OES";
+	case 0x8B91: return "GL_PALETTE4_RGBA8_OES";
+	case 0x8B92: return "GL_PALETTE4_R5_G6_B5_OES";
+	case 0x8B93: return "GL_PALETTE4_RGBA4_OES";
+	case 0x8B94: return "GL_PALETTE4_RGB5_A1_OES";
+	case 0x8B95: return "GL_PALETTE8_RGB8_OES";
+	case 0x8B96: return "GL_PALETTE8_RGBA8_OES";
+	case 0x8B97: return "GL_PALETTE8_R5_G6_B5_OES";
+	case 0x8B98: return "GL_PALETTE8_RGBA4_OES";
+	case 0x8B99: return "GL_PALETTE8_RGB5_A1_OES";
+	case 0x93B0: return "GL_COMPRESSED_RGBA_ASTC_4";
+	case 0x93B1: return "GL_COMPRESSED_RGBA_ASTC_5";
+	case 0x93B2: return "GL_COMPRESSED_RGBA_ASTC_5";
+	case 0x93B3: return "GL_COMPRESSED_RGBA_ASTC_6";
+	case 0x93B4: return "GL_COMPRESSED_RGBA_ASTC_6";
+	case 0x93B5: return "GL_COMPRESSED_RGBA_ASTC_8";
+	case 0x93B6: return "GL_COMPRESSED_RGBA_ASTC_8";
+	case 0x93B7: return "GL_COMPRESSED_RGBA_ASTC_8";
+	case 0x93B8: return "GL_COMPRESSED_RGBA_ASTC_10";
+	case 0x93B9: return "GL_COMPRESSED_RGBA_ASTC_10";
+	case 0x93BA: return "GL_COMPRESSED_RGBA_ASTC_10";
+	case 0x93BB: return "GL_COMPRESSED_RGBA_ASTC_10";
+	case 0x93BC: return "GL_COMPRESSED_RGBA_ASTC_12";
+	case 0x93BD: return "GL_COMPRESSED_RGBA_ASTC_12";
+	case 0x93D0: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4";
+	case 0x93D1: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5";
+	case 0x93D2: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5";
+	case 0x93D3: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6";
+	case 0x93D4: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6";
+	case 0x93D5: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8";
+	case 0x93D6: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8";
+	case 0x93D7: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8";
+	case 0x93D8: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10";
+	case 0x93D9: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10";
+	case 0x93DA: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10";
+	case 0x93DB: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10";
+	case 0x93DC: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12";
+	case 0x93DD: return "GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12";
+	default:
+		break;
+	}
+	return "unknown";
+}
+
+void print_compressed_formats(void)
+{
+	int i, num_fmt;
+	int *fmtlist;
+
+	glGetIntegerv(GL_NUM_COMPRESSED_TEXTURE_FORMATS, &num_fmt);
+	printf("%d generic compressed texture formats available:\n", num_fmt);
+
+	if(!(fmtlist = malloc(num_fmt * sizeof *fmtlist))) {
+		fprintf(stderr, "failed to allocate texture formats enumeration buffer\n");
+		return;
+	}
+	glGetIntegerv(GL_COMPRESSED_TEXTURE_FORMATS, fmtlist);
+
+	for(i=0; i<num_fmt; i++) {
+		printf(" %05x: %s\n", fmtlist[i], fmtstr(fmtlist[i]));
+	}
+	free(fmtlist);
+}
-- 
1.7.10.4