/*
 * Copyright 2014 Advanced Micro Devices, Inc.
 * All Rights Reserved.
 *
 * 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.
 */

#include "si_build_pm4.h"

/* For MSAA sample positions. */
#define FILL_SREG(s0x, s0y, s1x, s1y, s2x, s2y, s3x, s3y)  \
	((((unsigned)(s0x) & 0xf) << 0)  | (((unsigned)(s0y) & 0xf) << 4)  | \
	 (((unsigned)(s1x) & 0xf) << 8)  | (((unsigned)(s1y) & 0xf) << 12) | \
	 (((unsigned)(s2x) & 0xf) << 16) | (((unsigned)(s2y) & 0xf) << 20) | \
	 (((unsigned)(s3x) & 0xf) << 24) | (((unsigned)(s3y) & 0xf) << 28))

/* For obtaining location coordinates from registers */
#define SEXT4(x)		((int)((x) | ((x) & 0x8 ? 0xfffffff0 : 0)))
#define GET_SFIELD(reg, index)	SEXT4(((reg) >> ((index) * 4)) & 0xf)
#define GET_SX(reg, index)	GET_SFIELD((reg)[(index) / 4], ((index) % 4) * 2)
#define GET_SY(reg, index)	GET_SFIELD((reg)[(index) / 4], ((index) % 4) * 2 + 1)

/* The following sample ordering is required by EQAA.
 *
 * Sample 0 is approx. in the top-left quadrant.
 * Sample 1 is approx. in the bottom-right quadrant.
 *
 * Sample 2 is approx. in the bottom-left quadrant.
 * Sample 3 is approx. in the top-right quadrant.
 * (sample I={2,3} adds more detail to the vicinity of sample I-2)
 *
 * Sample 4 is approx. in the same quadrant as sample 0. (top-left)
 * Sample 5 is approx. in the same quadrant as sample 1. (bottom-right)
 * Sample 6 is approx. in the same quadrant as sample 2. (bottom-left)
 * Sample 7 is approx. in the same quadrant as sample 3. (top-right)
 * (sample I={4,5,6,7} adds more detail to the vicinity of sample I-4)
 *
 * The next 8 samples add more detail to the vicinity of the previous samples.
 * (sample I (I >= 8) adds more detail to the vicinity of sample I-8)
 *
 * The ordering is specified such that:
 *   If we take the first 2 samples, we should get good 2x MSAA.
 *   If we add 2 more samples, we should get good 4x MSAA with the same sample locations.
 *   If we add 4 more samples, we should get good 8x MSAA with the same sample locations.
 *   If we add 8 more samples, we should get perfect 16x MSAA with the same sample locations.
 *
 * The ordering also allows finding samples in the same vicinity.
 *
 * Group N of 2 samples in the same vicinity in 16x MSAA: {N,N+8}
 * Group N of 2 samples in the same vicinity in 8x MSAA: {N,N+4}
 * Group N of 2 samples in the same vicinity in 4x MSAA: {N,N+2}
 *
 * Groups of 4 samples in the same vicinity in 16x MSAA:
 *   Top left:     {0,4,8,12}
 *   Bottom right: {1,5,9,13}
 *   Bottom left:  {2,6,10,14}
 *   Top right:    {3,7,11,15}
 *
 * Groups of 4 samples in the same vicinity in 8x MSAA:
 *   Left half:  {0,2,4,6}
 *   Right half: {1,3,5,7}
 *
 * Groups of 8 samples in the same vicinity in 16x MSAA:
 *   Left half:  {0,2,4,6,8,10,12,14}
 *   Right half: {1,3,5,7,9,11,13,15}
 */

/* 1x MSAA */
static const uint32_t sample_locs_1x =
	FILL_SREG( 0, 0,   0, 0,   0, 0,   0, 0); /* S1, S2, S3 fields are not used by 1x */
static const uint64_t centroid_priority_1x = 0x0000000000000000ull;

/* 2x MSAA */
static const uint32_t sample_locs_2x =
	FILL_SREG(-4,-4,   4, 4,   0, 0,   0, 0); /* S2 & S3 fields are not used by 2x MSAA */
static const uint64_t centroid_priority_2x = 0x1010101010101010ull;

/* 4x, 8x, and 16x MSAA
 * - The first 4 locations happen to be optimal for 4x MSAA, better than
 *   the standard DX 4x locations.
 * - The first 8 locations happen to be almost as good as 8x DX locations,
 *   but the DX locations are horrible for worst-case EQAA 8s4f and 8s2f.
 */
static const uint32_t sample_locs_4x_8x_16x[] = {
	FILL_SREG(-5,-2,   5, 3,  -2, 6,   3,-5),
	FILL_SREG(-6,-7,   1, 1,  -6, 4,   7,-3),
	FILL_SREG(-1,-3,   6, 7,  -3, 2,   0,-7),
	FILL_SREG(-4,-6,   2, 5,  -8, 0,   4,-1),
};
static const uint64_t centroid_priority_4x = 0x2310231023102310ull;
static const uint64_t centroid_priority_8x = 0x4762310547623105ull;
static const uint64_t centroid_priority_16x = 0x49e7c6b231d0fa85ull;

static void si_get_sample_position(struct pipe_context *ctx, unsigned sample_count,
				   unsigned sample_index, float *out_value)
{
	const uint32_t *sample_locs;

	switch (sample_count) {
	case 1:
	default:
		sample_locs = &sample_locs_1x;
		break;
	case 2:
		sample_locs = &sample_locs_2x;
		break;
	case 4:
	case 8:
	case 16:
		sample_locs = sample_locs_4x_8x_16x;
		break;
	}

	out_value[0] = (GET_SX(sample_locs, sample_index) + 8) / 16.0f;
	out_value[1] = (GET_SY(sample_locs, sample_index) + 8) / 16.0f;
}

static void si_emit_max_4_sample_locs(struct radeon_winsys_cs *cs,
				      uint64_t centroid_priority,
				      uint32_t sample_locs)
{
	radeon_set_context_reg_seq(cs, R_028BD4_PA_SC_CENTROID_PRIORITY_0, 2);
	radeon_emit(cs, centroid_priority);
	radeon_emit(cs, centroid_priority >> 32);
	radeon_set_context_reg(cs, R_028BF8_PA_SC_AA_SAMPLE_LOCS_PIXEL_X0Y0_0, sample_locs);
	radeon_set_context_reg(cs, R_028C08_PA_SC_AA_SAMPLE_LOCS_PIXEL_X1Y0_0, sample_locs);
	radeon_set_context_reg(cs, R_028C18_PA_SC_AA_SAMPLE_LOCS_PIXEL_X0Y1_0, sample_locs);
	radeon_set_context_reg(cs, R_028C28_PA_SC_AA_SAMPLE_LOCS_PIXEL_X1Y1_0, sample_locs);
}

static void si_emit_max_16_sample_locs(struct radeon_winsys_cs *cs,
				       uint64_t centroid_priority,
				       const uint32_t *sample_locs,
				       unsigned num_samples)
{
	radeon_set_context_reg_seq(cs, R_028BD4_PA_SC_CENTROID_PRIORITY_0, 2);
	radeon_emit(cs, centroid_priority);
	radeon_emit(cs, centroid_priority >> 32);
	radeon_set_context_reg_seq(cs, R_028BF8_PA_SC_AA_SAMPLE_LOCS_PIXEL_X0Y0_0,
				   num_samples == 8 ? 14 : 16);
	radeon_emit_array(cs, sample_locs, 4);
	radeon_emit_array(cs, sample_locs, 4);
	radeon_emit_array(cs, sample_locs, 4);
	radeon_emit_array(cs, sample_locs, num_samples == 8 ? 2 : 4);
}

void si_emit_sample_locations(struct radeon_winsys_cs *cs, int nr_samples)
{
	switch (nr_samples) {
	default:
	case 1:
		si_emit_max_4_sample_locs(cs, centroid_priority_1x, sample_locs_1x);
		break;
	case 2:
		si_emit_max_4_sample_locs(cs, centroid_priority_2x, sample_locs_2x);
		break;
	case 4:
		si_emit_max_4_sample_locs(cs, centroid_priority_4x, sample_locs_4x_8x_16x[0]);
		break;
	case 8:
		si_emit_max_16_sample_locs(cs, centroid_priority_8x, sample_locs_4x_8x_16x, 8);
		break;
	case 16:
		si_emit_max_16_sample_locs(cs, centroid_priority_16x, sample_locs_4x_8x_16x, 16);
		break;
	}
}

void si_init_msaa_functions(struct si_context *sctx)
{
	int i;

	sctx->b.get_sample_position = si_get_sample_position;

	si_get_sample_position(&sctx->b, 1, 0, sctx->sample_locations_1x[0]);

	for (i = 0; i < 2; i++)
		si_get_sample_position(&sctx->b, 2, i, sctx->sample_locations_2x[i]);
	for (i = 0; i < 4; i++)
		si_get_sample_position(&sctx->b, 4, i, sctx->sample_locations_4x[i]);
	for (i = 0; i < 8; i++)
		si_get_sample_position(&sctx->b, 8, i, sctx->sample_locations_8x[i]);
	for (i = 0; i < 16; i++)
		si_get_sample_position(&sctx->b, 16, i, sctx->sample_locations_16x[i]);
}