/*
 * Copyright (c) 2013 Intel Corporation
 *
 * 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 interpolate-at-centroid.c
 *
 * Test ARB_gpu_shader5 interpolateAtCentroid builtin interaction with varying packing.
 *
 * Tests that interpolateAtCentroid(x) gives the same result as
 * declaring x as `centroid in`.
 *
 * R, 1-G channels are interesting; a correct implementation should produce
 * (0,1,0) in all pixels.
 *
 * We require 3.2, so the following assumptions are made:
 * - MAX_SAMPLES >= 4 (although we dont require exactly 4 samples; if only an
 *   8x mode is supported, the test should still work)
 * - GLSL 1.50 and Multisample textures are supported.
 *
 * This variant sets up the varyings so that `unqualified` will land in the second half
 * of a packed vec4 with the i965 driver, which exercises a tricky case.
 */


#include "piglit-util-gl.h"

PIGLIT_GL_TEST_CONFIG_BEGIN

	config.supports_gl_core_version = 32;

	config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGB;
	config.khr_no_error_support = PIGLIT_NO_ERRORS;

PIGLIT_GL_TEST_CONFIG_END

GLuint ms_fbo, vao, bo;
GLint draw_prog, test_prog;

float green[] = { 0, 1, 0 };
float verts[][2] = { { -1, -1 }, { 1, -1 }, { -1, 1 }, { 1, 1 }, };
#define GAIN "5"			/* multiplier for absolute difference; make the error more visible. */


enum piglit_result
piglit_display(void)
{
	bool pass = true;
	glViewport(0, 0, 64, 64);

	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo);
	glUseProgram(draw_prog);
	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, piglit_winsys_fbo);
	glUseProgram(test_prog);
	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

	pass = piglit_probe_rect_rgb(0, 0, 64, 64, green) && pass;

	piglit_present_results();

	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
}


void
piglit_init(int argc, char**argv)
{
	GLuint tex;
	piglit_require_extension("GL_ARB_gpu_shader5");

	glGenFramebuffers(1, &ms_fbo);
	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo);
	glGenTextures(1, &tex);
	glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, tex);
	glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, 4,
				GL_RGBA, 64, 64, GL_TRUE);
	glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
			       GL_TEXTURE_2D_MULTISAMPLE, tex, 0);

	if (!piglit_check_gl_error(GL_NO_ERROR)) {
		printf("fbo setup failed.\n");
		piglit_report_result(PIGLIT_SKIP);
	}

	draw_prog = piglit_build_simple_program(
		"#version 150\n"
		"in vec2 p;\n"
		"out vec2 pad;\n"
		"out vec2 unqualified;\n"
		"centroid out vec2 centroid_qualified;\n"
		"void main() {\n"
		"	gl_Position = vec4(p, 0, 1);\n"
		"	unqualified = p;\n"
		"	pad = vec2(0);\n"
		"	centroid_qualified = p;\n"
		"}\n",

		"#version 150\n"
		"#extension GL_ARB_gpu_shader5: require\n"
		"in vec2 pad;\n"		/* padding to exercise varying-packing interaction */
		"in vec2 unqualified;\n"
		"centroid in vec2 centroid_qualified;\n"
		"void main() {\n"
		"	gl_FragColor = vec4(" GAIN " * abs(\n"
		"		interpolateAtCentroid(unqualified) - centroid_qualified + pad), 0, 1);\n"
		"}\n");
	if (!draw_prog) {
		printf("draw_prog compile/link failed\n");
		piglit_report_result(PIGLIT_FAIL);
	}

	test_prog = piglit_build_simple_program(
		"#version 150\n"
		"in vec2 p;\n"
		"void main() {\n"
		"	gl_Position = vec4(p, 0, 1);\n"
		"}\n",

		"#version 150\n"
		"uniform sampler2DMS s;\n"
		"void main() {\n"
		"	vec4 temp = \n"
		"		texelFetch(s, ivec2(gl_FragCoord.xy), 0) +\n"
		"		texelFetch(s, ivec2(gl_FragCoord.xy), 1) +\n"
		"		texelFetch(s, ivec2(gl_FragCoord.xy), 2) +\n"
		"		texelFetch(s, ivec2(gl_FragCoord.xy), 3);\n"
		"	gl_FragColor = vec4(temp.x, 1-temp.y, temp.z, temp.w);\n"
		"}\n");
	if (!test_prog) {
		printf("test_prog compile/link failed\n");
		piglit_report_result(PIGLIT_FAIL);
	}

	glUseProgram(test_prog);
	glUniform1i(glGetUniformLocation(test_prog, "s"), 0);

	if (!piglit_check_gl_error(GL_NO_ERROR)) {
		printf("shader setup failed\n");
		piglit_report_result(PIGLIT_SKIP);
	}

	glGenVertexArrays(1, &vao);
	glBindVertexArray(vao);

	glEnableVertexAttribArray(0);
	glGenBuffers(1, &bo);
	glBindBuffer(GL_ARRAY_BUFFER, bo);
	glBufferData(GL_ARRAY_BUFFER, sizeof(verts), verts, GL_STATIC_DRAW);
	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, (GLvoid const *)0);
}