[Piglit] [PATCH] getteximage-formats: Add option to clear texture before rendering

[Topi Pohjolainen]

Demonstrates a bug in Intel color resolve logic. If rendering to
texture is preceded by fast clear subsequent reads from the
texture require the underlying color buffer to be resolved. In
case of mipmap generation Intel driver needs to reallocate the
underlying buffer to fit the subsequent levels. However, copy of
the original level zero to newly allocated buffer is delayed until
the driver is about to generate level one using level zero as
source. This causes a color resolve of the original level zero.
Both the generation of level one and the resolve are meta
operations, and the latter will interfere with the sampler
settings of the former.

Signed-off-by: Topi Pohjolainen <topi.pohjolainen at intel.com>
CC: Ian Romanick <idr at freedesktop.org>
---
 tests/all.py                          |  1 +
 tests/texturing/getteximage-formats.c | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/tests/all.py b/tests/all.py
index 2912d1f..8938bfc 100644
--- a/tests/all.py
+++ b/tests/all.py
@@ -2987,6 +2987,7 @@ with profile.group_manager(
     g(['fbo-storage-completeness'])
     g(['fbo-storage-formats'])
     g(['getteximage-formats', 'init-by-rendering'])
+    g(['getteximage-formats', 'init-by-clear-and-render'])
     g(['ext_framebuffer_multisample-fast-clear', 'single-sample'],
       'fbo-fast-clear')
     add_fbo_stencil_tests(g, 'GL_STENCIL_INDEX1')
diff --git a/tests/texturing/getteximage-formats.c b/tests/texturing/getteximage-formats.c
index 715d5df..320683f 100644
--- a/tests/texturing/getteximage-formats.c
+++ b/tests/texturing/getteximage-formats.c
@@ -50,6 +50,7 @@ static const char *TestName = "getteximage-formats";
 static const GLfloat clearColor[4] = { 0.4, 0.4, 0.4, 0.0 };
 static GLuint texture_id;
 static GLboolean init_by_rendering;
+static GLboolean init_by_clearing_first;
 
 #define TEX_SIZE 128
 
@@ -83,7 +84,7 @@ make_texture_image(GLenum intFormat, GLubyte upperRightTexel[4])
 
 	memcpy(upperRightTexel, tex[TEX_SIZE-1][TEX_SIZE-1], 4);
 
-	if (init_by_rendering) {
+	if (init_by_rendering || init_by_clearing_first) {
 		/* Initialize the mipmap levels. */
 		for (i = TEX_SIZE, j = 0; i; i >>= 1, j++) {
 			glTexImage2D(GL_TEXTURE_2D, j, intFormat, i, i, 0,
@@ -102,6 +103,11 @@ make_texture_image(GLenum intFormat, GLubyte upperRightTexel[4])
 			return GL_FALSE;
 		}
 
+		if (init_by_clearing_first) {
+			glClearColor(1, 0, 0, 1);
+			glClear(GL_COLOR_BUFFER_BIT);
+		}
+
 		glViewport(0, 0, TEX_SIZE, TEX_SIZE);
 
 		glWindowPos2iARB(0, 0);
@@ -365,6 +371,7 @@ test_format(const struct test_desc *test,
 	GLfloat expected[4], pix[4], tolerance[4];
 	GLboolean pass = GL_TRUE;
 
+	glClearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
 	glClear(GL_COLOR_BUFFER_BIT);
 
 	/* The RGBA_DXT1 formats seem to expose a Mesa/libtxc_dxtn bug.
@@ -536,6 +543,11 @@ piglit_init(int argc, char **argv)
 			puts("The textures will be initialized by rendering "
 			     "to them using glDrawPixels.");
 			break;
+		} else if (strcmp(argv[i], "init-by-clear-and-render") == 0) {
+			init_by_clearing_first = GL_TRUE;
+			puts("The textures will be initialized by rendering "
+			     "to them using glCear and glDrawPixels.");
+			break;
 		}
 	}
 
@@ -547,6 +559,4 @@ piglit_init(int argc, char **argv)
 	glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 
 	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-
-	glClearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
 }
-- 
2.5.0