[Piglit] [PATCH 2/2] arb_texture_view: check the initial value of GL_TEXTURE_MAX_LEVEL

[Nicolai Hähnle]

This test is a bit pedantic and the required behavior is perhaps
surprising, but it's what the spec says and it's compatible with
the clamping that Mesa does when you try to explicitly set a large
MAX_LEVEL via glTexParameteri.
---
 tests/spec/arb_texture_view/max-level.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tests/spec/arb_texture_view/max-level.c b/tests/spec/arb_texture_view/max-level.c
index ee25adf..b6dd326 100644
--- a/tests/spec/arb_texture_view/max-level.c
+++ b/tests/spec/arb_texture_view/max-level.c
@@ -77,6 +77,7 @@ test_max_level(void)
 	const unsigned int numPixels = WIDTH * HEIGHT;
 	GLuint texData[WIDTH * HEIGHT];
 	GLuint i, texFbo, tex, view, fbo, vertexArray, vertexBuf, l;
+	GLint level;
 
 	for (i = 0; i < numPixels; ++i) {
 		texData[i] = white;
@@ -119,6 +120,32 @@ test_max_level(void)
 	glTextureView(view, GL_TEXTURE_2D, tex, GL_RGBA8,
 		      VIEW_LEVEL, 1, 0, 1);
 	glBindTexture(GL_TEXTURE_2D, view);
+
+	/*
+	 * OpenGL 4.4 spec, section 8.14.3 says:
+	 *
+	 *   For immutable-format textures (see section 8.19), [...] level_max
+	 *   is then clamped to the range [level_base , level_immut − 1], [...]
+	 *   where level_immut is the levels parameter passed to TexStorage*
+	 *   for the texture object (the value of TEXTURE_IMMUTABLE_LEVELS;
+	 *   see section 8.19).
+	 *
+	 * and section 8.18 says this about glTextureView:
+	 *
+	 *   If the command is successful, the texture parameters in texture
+	 *   are updated as follows:
+	 *   [...]
+	 *    * TEXTURE_IMMUTABLE_LEVELS is set to the value of TEXTURE_-
+	 *      IMMUTABLE_LEVELS for origtexture.
+	 *
+	 */
+	glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, &level);
+	if (level != LEVELS - 1) {
+		printf("GL_TEXTURE_MAX_LEVEL is %d instead of %d after "
+		       "glTextureView\n", level, LEVELS - 1);
+		return false;
+	}
+
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
 
-- 
2.1.4