[Piglit] [PATCH 1/3] piglit: add compressed texture helper functions

[Brian Paul]

---
 tests/util/piglit-util-gl-common.c |   85 ++++++++++++++++++++++++++++++++++++
 tests/util/piglit-util-gl-common.h |   13 ++++++
 2 files changed, 98 insertions(+), 0 deletions(-)

diff --git a/tests/util/piglit-util-gl-common.c b/tests/util/piglit-util-gl-common.c
index 03d7420..7a5b2c7 100644
--- a/tests/util/piglit-util-gl-common.c
+++ b/tests/util/piglit-util-gl-common.c
@@ -369,3 +369,88 @@ piglit_probe_rect_halves_equal_rgba(int x, int y, int w, int h)
 	free(pixels);
 	return 1;
 }
+
+
+/**
+ * Return block size info for a specific texture compression format.
+ * \param  bw returns the block width, in pixels
+ * \param  bh returns the block height, in pixels
+ * \param  return number of bytes per block
+ * \return true if format is a known compressed format, false otherwise
+ */
+bool
+piglit_get_compressed_block_size(GLenum format,
+				 unsigned *bw, unsigned *bh, unsigned *bytes)
+{
+	switch (format) {
+	case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+	case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
+	case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
+	case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
+	case GL_COMPRESSED_RED_RGTC1:
+	case GL_COMPRESSED_SIGNED_RED_RGTC1:
+	case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
+	case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
+		*bw = *bh = 4;
+		*bytes = 8;
+		return true;
+	case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+	case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+	case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
+	case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
+	case GL_COMPRESSED_RG_RGTC2:
+	case GL_COMPRESSED_SIGNED_RG_RGTC2:
+	case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
+	case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
+		*bw = *bh = 4;
+		*bytes = 16;
+		return true;
+	case GL_COMPRESSED_RGB_FXT1_3DFX:
+	case GL_COMPRESSED_RGBA_FXT1_3DFX:
+		*bw = 8;
+		*bh = 4;
+		*bytes = 16;
+		return true;
+	default:
+		/* return something rather than uninitialized values */
+		*bw = *bh = *bytes = 1;
+		return false;
+	}
+}
+
+
+/**
+ * Compute size (in bytes) neede to store an image in the given compressed
+ * format.
+ */
+unsigned
+piglit_compressed_image_size(GLenum format, unsigned width, unsigned height)
+{
+	unsigned bw, bh, bytes;
+	bool b = piglit_get_compressed_block_size(format, &bw, &bh, &bytes);
+	assert(b);
+	return ((width + bw - 1) / bw) * ((height + bh - 1) / bh) * bytes;
+}
+
+
+/**
+ * Return offset (in bytes) to the given texel in a compressed image.
+ * Note the x and y must be multiples of the compressed block size.
+ */
+unsigned
+piglit_compressed_pixel_offset(GLenum format, unsigned width,
+			       unsigned x, unsigned y)
+{
+	unsigned bw, bh, bytes, offset;
+	bool b = piglit_get_compressed_block_size(format, &bw, &bh, &bytes);
+
+	assert(b);
+
+	assert(x % bw == 0);
+	assert(y % bh == 0);
+	assert(width % bw == 0);
+
+	offset = (width / bw * bytes * y / bh) + (x / bw * bytes);
+
+	return offset;
+}
diff --git a/tests/util/piglit-util-gl-common.h b/tests/util/piglit-util-gl-common.h
index 5fedd16..3380109 100644
--- a/tests/util/piglit-util-gl-common.h
+++ b/tests/util/piglit-util-gl-common.h
@@ -174,6 +174,19 @@ extern float piglit_tolerance[4];
 void piglit_set_tolerance_for_bits(int rbits, int gbits, int bbits, int abits);
 extern void piglit_require_transform_feedback(void);
 
+bool
+piglit_get_compressed_block_size(GLenum format,
+				 unsigned *bw, unsigned *bh, unsigned *bytes);
+
+unsigned
+piglit_compressed_image_size(GLenum format, unsigned width, unsigned height);
+
+unsigned
+piglit_compressed_pixel_offset(GLenum format, unsigned width,
+			       unsigned x, unsigned y);
+
+
+
 extern GLfloat cube_face_texcoords[6][4][3];
 extern const char *cube_face_names[6];
 extern const GLenum cube_face_targets[6];
-- 
1.7.3.4