/*
 * Copyright 2012 Advanced Micro Devices, 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
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS 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 "r600_cs.h"
#include "tgsi/tgsi_scan.h"

#define GET_MAX_SCISSOR(rctx) (rctx->chip_class >= EVERGREEN ? 16384 : 8192)

static void r600_set_scissor_states(struct pipe_context *ctx,
				    unsigned start_slot,
				    unsigned num_scissors,
				    const struct pipe_scissor_state *state)
{
	struct r600_common_context *rctx = (struct r600_common_context *)ctx;
	int i;

	for (i = 0; i < num_scissors; i++)
		rctx->scissors.states[start_slot + i] = state[i];

	if (!rctx->scissor_enabled)
		return;

	rctx->scissors.dirty_mask |= ((1 << num_scissors) - 1) << start_slot;
	rctx->set_atom_dirty(rctx, &rctx->scissors.atom, true);
}

/* Since the guard band disables clipping, we have to clip per-pixel
 * using a scissor.
 */
static void r600_get_scissor_from_viewport(struct r600_common_context *rctx,
					   const struct pipe_viewport_state *vp,
					   struct r600_signed_scissor *scissor)
{
	float tmp, minx, miny, maxx, maxy;

	/* Convert (-1, -1) and (1, 1) from clip space into window space. */
	minx = -vp->scale[0] + vp->translate[0];
	miny = -vp->scale[1] + vp->translate[1];
	maxx = vp->scale[0] + vp->translate[0];
	maxy = vp->scale[1] + vp->translate[1];

	/* r600_draw_rectangle sets this. Disable the scissor. */
	if (minx == -1 && miny == -1 && maxx == 1 && maxy == 1) {
		scissor->minx = scissor->miny = 0;
		scissor->maxx = scissor->maxy = GET_MAX_SCISSOR(rctx);
		return;
	}

	/* Handle inverted viewports. */
	if (minx > maxx) {
		tmp = minx;
		minx = maxx;
		maxx = tmp;
	}
	if (miny > maxy) {
		tmp = miny;
		miny = maxy;
		maxy = tmp;
	}

	/* Convert to integer and round up the max bounds. */
	scissor->minx = minx;
	scissor->miny = miny;
	scissor->maxx = ceilf(maxx);
	scissor->maxy = ceilf(maxy);
}

static void r600_clamp_scissor(struct r600_common_context *rctx,
			       struct pipe_scissor_state *out,
			       struct r600_signed_scissor *scissor)
{
	unsigned max_scissor = GET_MAX_SCISSOR(rctx);
	out->minx = CLAMP(scissor->minx, 0, max_scissor);
	out->miny = CLAMP(scissor->miny, 0, max_scissor);
	out->maxx = CLAMP(scissor->maxx, 0, max_scissor);
	out->maxy = CLAMP(scissor->maxy, 0, max_scissor);
}

static void r600_clip_scissor(struct pipe_scissor_state *out,
			      struct pipe_scissor_state *clip)
{
	out->minx = MAX2(out->minx, clip->minx);
	out->miny = MAX2(out->miny, clip->miny);
	out->maxx = MIN2(out->maxx, clip->maxx);
	out->maxy = MIN2(out->maxy, clip->maxy);
}

static void r600_scissor_make_union(struct r600_signed_scissor *out,
				    struct r600_signed_scissor *in)
{
	out->minx = MIN2(out->minx, in->minx);
	out->miny = MIN2(out->miny, in->miny);
	out->maxx = MAX2(out->maxx, in->maxx);
	out->maxy = MAX2(out->maxy, in->maxy);
}

void evergreen_apply_scissor_bug_workaround(struct r600_common_context *rctx,
					    struct pipe_scissor_state *scissor)
{
	if (rctx->chip_class == EVERGREEN || rctx->chip_class == CAYMAN) {
		if (scissor->maxx == 0)
			scissor->minx = 1;
		if (scissor->maxy == 0)
			scissor->miny = 1;

		if (rctx->chip_class == CAYMAN &&
		    scissor->maxx == 1 && scissor->maxy == 1)
			scissor->maxx = 2;
	}
}

static void r600_emit_one_scissor(struct r600_common_context *rctx,
				  struct radeon_winsys_cs *cs,
				  struct r600_signed_scissor *vp_scissor,
				  struct pipe_scissor_state *scissor)
{
	struct pipe_scissor_state final;

	if (rctx->vs_disables_clipping_viewport) {
		final.minx = final.miny = 0;
		final.maxx = final.maxy = GET_MAX_SCISSOR(rctx);
	} else {
		r600_clamp_scissor(rctx, &final, vp_scissor);
	}

	if (scissor)
		r600_clip_scissor(&final, scissor);

	evergreen_apply_scissor_bug_workaround(rctx, &final);

	radeon_emit(cs, S_028250_TL_X(final.minx) |
			S_028250_TL_Y(final.miny) |
			S_028250_WINDOW_OFFSET_DISABLE(1));
	radeon_emit(cs, S_028254_BR_X(final.maxx) |
			S_028254_BR_Y(final.maxy));
}

/* the range is [-MAX, MAX] */
#define GET_MAX_VIEWPORT_RANGE(rctx) (rctx->chip_class >= EVERGREEN ? 32768 : 16384)

static void r600_emit_guardband(struct r600_common_context *rctx,
				struct r600_signed_scissor *vp_as_scissor)
{
	struct radeon_winsys_cs *cs = rctx->gfx.cs;
	struct pipe_viewport_state vp;
	float left, top, right, bottom, max_range, guardband_x, guardband_y;

	/* Reconstruct the viewport transformation from the scissor. */
	vp.translate[0] = (vp_as_scissor->minx + vp_as_scissor->maxx) / 2.0;
	vp.translate[1] = (vp_as_scissor->miny + vp_as_scissor->maxy) / 2.0;
	vp.scale[0] = vp_as_scissor->maxx - vp.translate[0];
	vp.scale[1] = vp_as_scissor->maxy - vp.translate[1];

	/* Treat a 0x0 viewport as 1x1 to prevent division by zero. */
	if (vp_as_scissor->minx == vp_as_scissor->maxx)
		vp.scale[0] = 0.5;
	if (vp_as_scissor->miny == vp_as_scissor->maxy)
		vp.scale[1] = 0.5;

	/* Find the biggest guard band that is inside the supported viewport
	 * range. The guard band is specified as a horizontal and vertical
	 * distance from (0,0) in clip space.
	 *
	 * This is done by applying the inverse viewport transformation
	 * on the viewport limits to get those limits in clip space.
	 *
	 * Use a limit one pixel smaller to allow for some precision error.
	 */
	max_range = GET_MAX_VIEWPORT_RANGE(rctx) - 1;
	left   = (-max_range - vp.translate[0]) / vp.scale[0];
	right  = ( max_range - vp.translate[0]) / vp.scale[0];
	top    = (-max_range - vp.translate[1]) / vp.scale[1];
	bottom = ( max_range - vp.translate[1]) / vp.scale[1];

	assert(left <= -1 && top <= -1 && right >= 1 && bottom >= 1);

	guardband_x = MIN2(-left, right);
	guardband_y = MIN2(-top, bottom);

	/* If any of the GB registers is updated, all of them must be updated. */
	if (rctx->chip_class >= CAYMAN)
		radeon_set_context_reg_seq(cs, CM_R_028BE8_PA_CL_GB_VERT_CLIP_ADJ, 4);
	else
		radeon_set_context_reg_seq(cs, R600_R_028C0C_PA_CL_GB_VERT_CLIP_ADJ, 4);

	radeon_emit(cs, fui(guardband_y)); /* R_028BE8_PA_CL_GB_VERT_CLIP_ADJ */
	radeon_emit(cs, fui(1.0));         /* R_028BEC_PA_CL_GB_VERT_DISC_ADJ */
	radeon_emit(cs, fui(guardband_x)); /* R_028BF0_PA_CL_GB_HORZ_CLIP_ADJ */
	radeon_emit(cs, fui(1.0));         /* R_028BF4_PA_CL_GB_HORZ_DISC_ADJ */
}

static void r600_emit_scissors(struct r600_common_context *rctx, struct r600_atom *atom)
{
	struct radeon_winsys_cs *cs = rctx->gfx.cs;
	struct pipe_scissor_state *states = rctx->scissors.states;
	unsigned mask = rctx->scissors.dirty_mask;
	bool scissor_enabled = rctx->scissor_enabled;
	struct r600_signed_scissor max_vp_scissor;
	int i;

	/* The simple case: Only 1 viewport is active. */
	if (!rctx->vs_writes_viewport_index) {
		struct r600_signed_scissor *vp = &rctx->viewports.as_scissor[0];

		if (!(mask & 1))
			return;

		radeon_set_context_reg_seq(cs, R_028250_PA_SC_VPORT_SCISSOR_0_TL, 2);
		r600_emit_one_scissor(rctx, cs, vp, scissor_enabled ? &states[0] : NULL);
		r600_emit_guardband(rctx, vp);
		rctx->scissors.dirty_mask &= ~1; /* clear one bit */
		return;
	}

	/* Shaders can draw to any viewport. Make a union of all viewports. */
	max_vp_scissor = rctx->viewports.as_scissor[0];
	for (i = 1; i < R600_MAX_VIEWPORTS; i++)
		r600_scissor_make_union(&max_vp_scissor,
				      &rctx->viewports.as_scissor[i]);

	while (mask) {
		int start, count, i;

		u_bit_scan_consecutive_range(&mask, &start, &count);

		radeon_set_context_reg_seq(cs, R_028250_PA_SC_VPORT_SCISSOR_0_TL +
					       start * 4 * 2, count * 2);
		for (i = start; i < start+count; i++) {
			r600_emit_one_scissor(rctx, cs, &rctx->viewports.as_scissor[i],
					      scissor_enabled ? &states[i] : NULL);
		}
	}
	r600_emit_guardband(rctx, &max_vp_scissor);
	rctx->scissors.dirty_mask = 0;
}

static void r600_set_viewport_states(struct pipe_context *ctx,
				     unsigned start_slot,
				     unsigned num_viewports,
				     const struct pipe_viewport_state *state)
{
	struct r600_common_context *rctx = (struct r600_common_context *)ctx;
	int i;

	for (i = 0; i < num_viewports; i++) {
		unsigned index = start_slot + i;

		rctx->viewports.states[index] = state[i];
		r600_get_scissor_from_viewport(rctx, &state[i],
					       &rctx->viewports.as_scissor[index]);
	}

	rctx->viewports.dirty_mask |= ((1 << num_viewports) - 1) << start_slot;
	rctx->scissors.dirty_mask |= ((1 << num_viewports) - 1) << start_slot;
	rctx->set_atom_dirty(rctx, &rctx->viewports.atom, true);
	rctx->set_atom_dirty(rctx, &rctx->scissors.atom, true);
}

static void r600_emit_viewports(struct r600_common_context *rctx, struct r600_atom *atom)
{
	struct radeon_winsys_cs *cs = rctx->gfx.cs;
	struct pipe_viewport_state *states = rctx->viewports.states;
	unsigned mask = rctx->viewports.dirty_mask;

	/* The simple case: Only 1 viewport is active. */
	if (!rctx->vs_writes_viewport_index) {
		if (!(mask & 1))
			return;

		radeon_set_context_reg_seq(cs, R_02843C_PA_CL_VPORT_XSCALE, 6);
		radeon_emit(cs, fui(states[0].scale[0]));
		radeon_emit(cs, fui(states[0].translate[0]));
		radeon_emit(cs, fui(states[0].scale[1]));
		radeon_emit(cs, fui(states[0].translate[1]));
		radeon_emit(cs, fui(states[0].scale[2]));
		radeon_emit(cs, fui(states[0].translate[2]));
		rctx->viewports.dirty_mask &= ~1; /* clear one bit */
		return;
	}

	while (mask) {
		int start, count, i;

		u_bit_scan_consecutive_range(&mask, &start, &count);

		radeon_set_context_reg_seq(cs, R_02843C_PA_CL_VPORT_XSCALE +
					       start * 4 * 6, count * 6);
		for (i = start; i < start+count; i++) {
			radeon_emit(cs, fui(states[i].scale[0]));
			radeon_emit(cs, fui(states[i].translate[0]));
			radeon_emit(cs, fui(states[i].scale[1]));
			radeon_emit(cs, fui(states[i].translate[1]));
			radeon_emit(cs, fui(states[i].scale[2]));
			radeon_emit(cs, fui(states[i].translate[2]));
		}
	}
	rctx->viewports.dirty_mask = 0;
}

void r600_set_scissor_enable(struct r600_common_context *rctx, bool enable)
{
	if (rctx->scissor_enabled != enable) {
		rctx->scissor_enabled = enable;
		rctx->scissors.dirty_mask = (1 << R600_MAX_VIEWPORTS) - 1;
		rctx->set_atom_dirty(rctx, &rctx->scissors.atom, true);
	}
}

/**
 * Normally, we only emit 1 viewport and 1 scissor if no shader is using
 * the VIEWPORT_INDEX output, and emitting the other viewports and scissors
 * is delayed. When a shader with VIEWPORT_INDEX appears, this should be
 * called to emit the rest.
 */
void r600_update_vs_writes_viewport_index(struct r600_common_context *rctx,
					  struct tgsi_shader_info *info)
{
	bool vs_window_space;

	if (!info)
		return;

	/* When the VS disables clipping and viewport transformation. */
	vs_window_space =
		info->properties[TGSI_PROPERTY_VS_WINDOW_SPACE_POSITION];

	if (rctx->vs_disables_clipping_viewport != vs_window_space) {
		rctx->vs_disables_clipping_viewport = vs_window_space;
		rctx->scissors.dirty_mask = (1 << R600_MAX_VIEWPORTS) - 1;
		rctx->set_atom_dirty(rctx, &rctx->scissors.atom, true);
	}

	/* Viewport index handling. */
	rctx->vs_writes_viewport_index = info->writes_viewport_index;
	if (!rctx->vs_writes_viewport_index)
		return;

	if (rctx->scissors.dirty_mask)
	    rctx->set_atom_dirty(rctx, &rctx->scissors.atom, true);
	if (rctx->viewports.dirty_mask)
	    rctx->set_atom_dirty(rctx, &rctx->viewports.atom, true);
}

void r600_init_viewport_functions(struct r600_common_context *rctx)
{
	rctx->scissors.atom.emit = r600_emit_scissors;
	rctx->viewports.atom.emit = r600_emit_viewports;

	rctx->scissors.atom.num_dw = (2 + 16 * 2) + 6;
	rctx->viewports.atom.num_dw = 2 + 16 * 6;

	rctx->b.set_scissor_states = r600_set_scissor_states;
	rctx->b.set_viewport_states = r600_set_viewport_states;
}