[Piglit] [PATCH] gl-3.2-compat: test gl_FogFragCoord built-in with geometry shaders

[Timothy Arceri]

This extends the fogscale test to test a gl_FogFragCoord value
passed via a geometry shader.
---
 tests/shaders/glsl-fs-fogscale.c | 100 +++++++++++++++++++++++++------
 1 file changed, 82 insertions(+), 18 deletions(-)

diff --git a/tests/shaders/glsl-fs-fogscale.c b/tests/shaders/glsl-fs-fogscale.c
index e5f28eaf7..076092d07 100644
--- a/tests/shaders/glsl-fs-fogscale.c
+++ b/tests/shaders/glsl-fs-fogscale.c
@@ -39,13 +39,34 @@ PIGLIT_GL_TEST_CONFIG_BEGIN
 
 PIGLIT_GL_TEST_CONFIG_END
 
-enum piglit_result
-piglit_display(void)
+static const char vs_source[] =
+	"void main()\n"
+	"{\n"
+	"	gl_Position = gl_Vertex;\n"
+	"	gl_FogFragCoord = gl_Position.x;\n"
+	"}\n";
+
+static const char *dummy_vs_source =
+	"void main()\n"
+	"{\n"
+	"	gl_Position = gl_Vertex;\n"
+	"}\n";
+
+static const char fs_source[] =
+	"void main()\n"
+	"{\n"
+	"	gl_FragColor = vec4(gl_FogFragCoord * gl_Fog.scale * vec2(1.0, -1.0), 0.0, 1.0);\n"
+	"}\n";
+
+static bool
+test_prog(unsigned prog, const char *test_name)
 {
 	static const float green[] = {0.0f, 1.0f, 0.0f, 1.0f};
 	static const float red[] = {1.0f, 0.0f, 0.0f, 1.0f};
 	bool pass = true;
 
+	glUseProgram(prog);
+
 	glClearColor(0.0, 0.0, 1.0, 0.0);
 	glClear(GL_COLOR_BUFFER_BIT);
 
@@ -57,30 +78,73 @@ piglit_display(void)
 				      piglit_width / 2, piglit_height,
 				      red) && pass;
 
-	piglit_present_results();
+	piglit_report_subtest_result(pass ? PIGLIT_PASS : PIGLIT_FAIL, "%s",
+				     test_name);
 
-	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
+	return pass;
 }
 
-void
-piglit_init(int argc, char **argv)
+static void
+create_gs_source(char **gs_source, char *fogFragCoordValue)
 {
-	static const char vs_source[] =
+	(void)!asprintf(gs_source,
+		"#version 150 compatibility\n"
+		"layout(triangles) in;\n"
+		"layout(triangle_strip, max_vertices = 3) out;\n"
+		"\n"
 		"void main()\n"
 		"{\n"
-		"	gl_Position = gl_Vertex;\n"
-		"	gl_FogFragCoord = gl_Position.x;\n"
-		"}\n";
-	static const char fs_source[] =
-		"void main()\n"
-		"{\n"
-		"	gl_FragColor = vec4(gl_FogFragCoord * gl_Fog.scale * vec2(1.0, -1.0), 0.0, 1.0);\n"
-		"}\n";
-	GLuint prog;
+		"	for (int i = 0; i < 3; i++) {\n"
+		"		gl_Position = gl_in[i].gl_Position;\n"
+		"		gl_FogFragCoord = %s;\n"
+		"		EmitVertex();\n"
+		"	}\n"
+		"}\n",
+		fogFragCoordValue);
+}
+
+enum piglit_result
+piglit_display(void)
+{
+	bool pass = true;
+	char *gs_source;
+	char *gs_source2;
+
+	/* Test simple vs and fs program */
+	GLuint prog = piglit_build_simple_program(vs_source, fs_source);
+	test_prog(prog, "vs and fs");
+
+	/* Test passing gl_FogFragCoord via the Geometry Shader */
+	if (piglit_get_gl_version() >= 32) {
+		/* Test gl_FogFragCoord gs output only */
+		create_gs_source(&gs_source, "gl_Position.x");
+		prog = piglit_build_simple_program_multiple_shaders(
+			GL_VERTEX_SHADER, dummy_vs_source,
+			GL_GEOMETRY_SHADER, gs_source,
+			GL_FRAGMENT_SHADER, fs_source,
+			0);
+		pass = pass && test_prog(prog, "gs-out and fs");
+
+		/* Test gl_FogFragCoord both as a gs output and input */
+		create_gs_source(&gs_source2, "gl_in[i].gl_FogFragCoord");
+		prog = piglit_build_simple_program_multiple_shaders(
+			GL_VERTEX_SHADER, vs_source,
+			GL_GEOMETRY_SHADER, gs_source2,
+			GL_FRAGMENT_SHADER, fs_source,
+			0);
+		pass = pass && test_prog(prog, "vs, gs and fs");
 
-	prog = piglit_build_simple_program(vs_source, fs_source);
+	} else {
+		piglit_report_subtest_result(PIGLIT_SKIP, "gs-out and fs");
+		piglit_report_subtest_result(PIGLIT_SKIP, "vs, gs and fs");
+	}
 
+	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
+}
+
+void
+piglit_init(int argc, char **argv)
+{
 	glFogf(GL_FOG_START, 0.0f);
 	glFogf(GL_FOG_END, 0.0f);
-	glUseProgram(prog);
 }
-- 
2.17.0