glsl-1.30: add basic test for testing textureOffset functionality.

This is pretty rough and doesn't really test all that much (just
textureOffsetLod, but there's other texturing functions with offsets),
doesn't test different wrap modes, NPOT sizes etc., but there's no
other test using "ordinary" texture opcodes and texel offsets, so
it's a start (and in fact it exposed a bug in the mesa state tracker).
Tested with llvmpipe (pass) and softpipe (fail) which is as expected -
hopefully the math is ok...
Inspired from fs-texelFetchOffset.

v2: some minor comment and code fixes

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

2 files changed, 157 insertions, 0 deletions

diff --git a/tests/spec/glsl-1.30/execution/CMakeLists.gl.txt b/tests/spec/glsl-1.30/execution/CMakeLists.gl.txt
index 6737bb19..3c0b2d51 100644
--- a/tests/spec/glsl-1.30/execution/CMakeLists.gl.txt
+++ b/tests/spec/glsl-1.30/execution/CMakeLists.gl.txt
@@ -13,6 +13,7 @@ link_libraries (
 piglit_add_executable (fs-discard-exit-2 fs-discard-exit-2.c)
 piglit_add_executable (fs-texelFetch-2D fs-texelFetch-2D.c)
 piglit_add_executable (fs-texelFetchOffset-2D fs-texelFetchOffset-2D.c)
+piglit_add_executable (fs-textureOffset-2D fs-textureOffset-2D.c)
 IF (NOT MSVC)
 	piglit_add_executable (isinf-and-isnan isinf-and-isnan.c)
 ENDIF (NOT MSVC)
diff --git a/tests/spec/glsl-1.30/execution/fs-textureOffset-2D.c b/tests/spec/glsl-1.30/execution/fs-textureOffset-2D.c
new file mode 100644
index 00000000..7ce2ec4d
--- /dev/null
+++ b/tests/spec/glsl-1.30/execution/fs-textureOffset-2D.c
@@ -0,0 +1,156 @@
+/*
+ * Copyright 2013 VMware, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file fs-textureOffset-2D.c
+ *
+ * Tests the built-in function textureLodOffset() in the fragment shader.
+ *
+ * Creates a mipmapped 64x32 2D texture and draws a series of squares whose
+ * color contains a texel fetched from each quadrant of the rgbw texture.
+ *
+ * Author: Roland Scheidegger
+ */
+#include "piglit-util-gl-common.h"
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+
+	config.supports_gl_compat_version = 10;
+
+	config.window_visual = PIGLIT_GL_VISUAL_RGBA | PIGLIT_GL_VISUAL_DOUBLE;
+
+PIGLIT_GL_TEST_CONFIG_END
+
+const int tex_size = 64;
+
+static int pos_location, lod_location;
+
+static const char vert[] =
+"#version 130\n"
+"void main()\n"
+"{\n"
+"	gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+"}\n";
+
+static const char fragtexlodoffset[] =
+"#version 130\n"
+"uniform vec2 pos;\n"
+"uniform float lod;\n"
+"uniform sampler2D tex;\n"
+"void main()\n"
+"{\n"
+"       const ivec2 offset = ivec2(-2, 2);\n"
+"       vec4 texel = textureLodOffset(tex, pos, lod, offset);\n"
+"	gl_FragColor = texel;\n"
+"}\n";
+
+#ifdef _MSC_VER
+#undef max
+#endif
+static float max(float x, float y) { return (x > y) ? x : y; }
+
+enum piglit_result
+piglit_display(void)
+{
+	int l, q;
+	bool pass = true;
+	float red[4]   = {1.0, 0.0, 0.0, 1.0};
+	float green[4]   = {0.0, 1.0, 0.0, 1.0};
+	float blue[4]  = {0.0, 0.0, 1.0, 1.0};
+	float white[4]  = {1.0, 1.0, 1.0, 1.0};
+	float undefined[4] = {0.0, 0.0, 0.0, 0.0};
+
+	piglit_ortho_projection(piglit_width, piglit_height, false);
+
+	glClearColor(0.5, 0.5, 0.5, 1.0);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	/* TODO: test other wrap modes */	
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+	for (l = 0; (tex_size >> l) > 0; l++) {
+		const int width = tex_size >> l;
+		const int height = max(width / 2, 1);
+		const int y = 10 + 20 * l;
+
+		glUniform1f(lod_location, (float)l);
+
+		/* Draw 4 squares with a color sample for each quad */
+		for (q = 0; q < 4; q++) {
+			const float tex_x = (q / 2) * 0.5f + 0.25f;
+			const float tex_y = (q % 2) * 0.5f + 0.25f;
+			float *c = undefined;
+			const int x = 10+20*q;
+
+			if (((q / 2) * 0.5f + 0.25f) * width + (-2.0f) < 0.5f * width) {
+				if (((q % 2) * 0.5f + 0.25f) * height + (+2.0f) < 0.5f * height)
+					c = red;
+				else
+					c = blue;
+			}
+			else {
+				if (((q % 2) * 0.5f + 0.25f) * height + (+2.0f) < 0.5f * height)
+					c = green;
+				else
+					c = white;
+			}
+				
+			glUniform2f(pos_location, tex_x, tex_y);
+			piglit_draw_rect(x, y, 10, 10);
+
+			if (width > 2 && c != undefined) /* below 1 wide no test */
+				pass &= piglit_probe_rect_rgba(x, y, 10, 10, c);
+		}
+	}
+
+	piglit_present_results();
+
+	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
+}
+
+void
+piglit_init(int argc, char **argv)
+{
+	int vs, fs, prog;
+
+	piglit_require_GLSL_version(130);
+
+	glActiveTexture(GL_TEXTURE0);
+	/* TODO: test npot sizes, other samplers, ... */
+	piglit_rgbw_texture(GL_RGBA, tex_size, tex_size / 2, true, false,
+			    GL_UNSIGNED_NORMALIZED);
+
+	/* TODO: test other texture instructions */
+	vs = piglit_compile_shader_text(GL_VERTEX_SHADER, vert);
+	fs = piglit_compile_shader_text(GL_FRAGMENT_SHADER, fragtexlodoffset);
+	prog = piglit_link_simple_program(vs, fs);
+
+	lod_location = glGetUniformLocation(prog, "lod");
+	pos_location = glGetUniformLocation(prog, "pos");
+
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_NEAREST);
+
+	glUseProgram(prog);
+}