[Piglit] [PATCH 1/4] mulitsample-fast-clear: Test enabling GL_FRAMEBUFFER_SRGB

[Neil Roberts]

If ‘enable-fb-srgb’ is given on the command line to the fast clear
test it will now enable GL_FRAMEBUFFER_SRGB before clearing the
buffer. This should cause the clear color to be converted from SRGB to
linear before being written to the framebuffer. The expected color is
therefore converted to match. This exposes a bug on SKL in the i965
driver when clearing SRGB MSRTs.
---
 tests/all.py                                       |  4 ++
 .../spec/ext_framebuffer_multisample/fast-clear.c  | 63 ++++++++++++++++++----
 2 files changed, 57 insertions(+), 10 deletions(-)

diff --git a/tests/all.py b/tests/all.py
index 07e3599..fd07adb 100644
--- a/tests/all.py
+++ b/tests/all.py
@@ -2039,6 +2039,10 @@ with profile.group_manager(
     g(['framebuffer-srgb'], run_concurrent=False)
     g(['arb_framebuffer_srgb-clear'])
     g(['arb_framebuffer_srgb-pushpop'])
+    g(['ext_framebuffer_multisample-fast-clear',
+       'GL_EXT_texture_sRGB',
+       'enable-fb-srgb'],
+      'msaa-fast-clear')
 
 with profile.group_manager(
         PiglitGLTest,
diff --git a/tests/spec/ext_framebuffer_multisample/fast-clear.c b/tests/spec/ext_framebuffer_multisample/fast-clear.c
index b3b57bf..9634eeb 100644
--- a/tests/spec/ext_framebuffer_multisample/fast-clear.c
+++ b/tests/spec/ext_framebuffer_multisample/fast-clear.c
@@ -33,6 +33,13 @@
  * various different code paths to implement a fast clear optimisation
  * and the path taken depends on the color chosen to a certain
  * degree.
+ *
+ * The test can take the following additional arguments:
+ *
+ *  enable-fb-srgb: This will cause it to enable GL_FRAMEBUFFER_SRGB
+ *    before clearing the buffer so that it can test that the color
+ *    gets correctly converted to SRGB before being stored in the
+ *    color buffer.
  */
 
 #include "piglit-util-gl.h"
@@ -109,6 +116,36 @@ clear_colors[][4] = {
 };
 
 static GLuint prog_float, prog_int, prog_uint;
+static bool enable_fb_srgb = false;
+
+static void
+convert_srgb_color(const struct format_desc *format,
+		   float *color)
+{
+	int i;
+
+	/* If the texture is not an sRGB format then no conversion is
+	 * needed regardless of the sRGB settings.
+	 */
+	if (strstr(format->name, "SRGB") == NULL &&
+	    strstr(format->name, "SLUMINANCE") == NULL)
+		return;
+
+	/* If GL_FRAMEBUFFER_SRGB was enabled when we did the clear
+	 * then the clear color would have been converted to SRGB
+	 * before being written. When it is sampled it will be
+	 * converted back to linear. The two conversions cancel each
+	 * other out so we don't need to do anything.
+	 */
+	if (enable_fb_srgb)
+		return;
+
+	/* Otherwise we need to compensate for the color being
+	 * converted to linear when sampled.
+	 */
+	for (i = 0; i < 3; i++)
+		color[i] = piglit_srgb_to_linear(color[i]);
+}
 
 static enum piglit_result
 test_color(GLuint fbo,
@@ -119,10 +156,12 @@ test_color(GLuint fbo,
 {
 	float expected_color[4];
 	float alpha_override;
-	int i;
 
 	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 
+	if (enable_fb_srgb)
+		glEnable(GL_FRAMEBUFFER_SRGB);
+
 	switch (clear_type) {
 	case GL_INT: {
 		GLint clear_color_int[4] = {
@@ -167,6 +206,9 @@ test_color(GLuint fbo,
 		break;
 	}
 
+	if (enable_fb_srgb)
+		glDisable(GL_FRAMEBUFFER_SRGB);
+
 	memcpy(expected_color, clear_color, sizeof expected_color);
 
 	switch (format->base_internal_format) {
@@ -204,13 +246,7 @@ test_color(GLuint fbo,
 		break;
 	}
 
-	if (strstr(format->name, "SRGB") ||
-	    strstr(format->name, "SLUMINANCE")) {
-		for (i = 0; i < 3; i++) {
-			expected_color[i] =
-				piglit_srgb_to_linear(expected_color[i]);
-		}
-	}
+	convert_srgb_color(format, expected_color);
 
 	glBindFramebuffer(GL_FRAMEBUFFER, piglit_winsys_fbo);
 	piglit_draw_rect(offset * 16 * 2.0f / piglit_width - 1.0f,
@@ -395,9 +431,16 @@ piglit_init(int argc, char **argv)
 	int test_set_index = 0;
 	int glsl_major, glsl_minor;
 	bool es;
+	int i;
 
-	if (argc >= 2)
-		test_set_index = fbo_lookup_test_set(argv[1]);
+	for (i = 1; i < argc; i++) {
+		if (!strcmp(argv[i], "enable-fb-srgb")) {
+			enable_fb_srgb = true;
+			piglit_require_extension("GL_ARB_framebuffer_sRGB");
+		} else {
+			test_set_index = fbo_lookup_test_set(argv[i]);
+		}
+	}
 
 	piglit_require_extension("GL_ARB_texture_multisample");
 
-- 
1.9.3