/*
 * Copyright (C) 2010 Corbin Simpson
 *
 * 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 COPYRIGHT OWNER(S) AND/OR ITS 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 "radeon_program_tex.h"

/* Series of transformations to be done on textures. */

static struct rc_src_register shadow_ambient(struct r300_fragment_program_compiler *compiler,
											 int tmu)
{
	struct rc_src_register reg = { 0, };

	if (compiler->enable_shadow_ambient) {
		reg.File = RC_FILE_CONSTANT;
		reg.Index = rc_constants_add_state(&compiler->Base.Program.Constants,
										   RC_STATE_SHADOW_AMBIENT, tmu);
		reg.Swizzle = RC_SWIZZLE_WWWW;
	} else {
		reg.File = RC_FILE_NONE;
		reg.Swizzle = RC_SWIZZLE_0000;
	}
	return reg;
}

static void lower_texture_rect(struct r300_fragment_program_compiler *compiler,
							   struct rc_instruction *inst)
{
	struct rc_instruction *inst_rect;
	unsigned temp = rc_find_free_temporary(&compiler->Base);

	if (inst->U.I.TexSrcTarget == RC_TEXTURE_RECT ||
		compiler->state.unit[inst->U.I.TexSrcUnit].non_normalized_coords) {
		inst_rect = rc_insert_new_instruction(&compiler->Base, inst->Prev);

		inst_rect->U.I.Opcode = RC_OPCODE_MUL;
		inst_rect->U.I.DstReg.File = RC_FILE_TEMPORARY;
		inst_rect->U.I.DstReg.Index = temp;
		inst_rect->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
		inst_rect->U.I.SrcReg[1].File = RC_FILE_CONSTANT;
		inst_rect->U.I.SrcReg[1].Index =
				rc_constants_add_state(&compiler->Base.Program.Constants,
									   RC_STATE_R300_TEXRECT_FACTOR, inst->U.I.TexSrcUnit);

		reset_srcreg(&inst->U.I.SrcReg[0]);
		inst->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
		inst->U.I.SrcReg[0].Index = temp;

		inst->U.I.TexSrcTarget = RC_TEXTURE_2D;
	}
}

static void projective_divide(struct r300_fragment_program_compiler *compiler,
			      struct rc_instruction *inst)
{
	struct rc_instruction *inst_mul, *inst_rcp;

	unsigned temp = rc_find_free_temporary(&compiler->Base);

	inst_rcp = rc_insert_new_instruction(&compiler->Base, inst->Prev);
	inst_rcp->U.I.Opcode = RC_OPCODE_RCP;
	inst_rcp->U.I.DstReg.File = RC_FILE_TEMPORARY;
	inst_rcp->U.I.DstReg.Index = temp;
	inst_rcp->U.I.DstReg.WriteMask = RC_MASK_W;
	inst_rcp->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
	/* Because the input can be arbitrarily swizzled,
	 * read the component mapped to W. */
	inst_rcp->U.I.SrcReg[0].Swizzle =
		RC_MAKE_SWIZZLE_SMEAR(GET_SWZ(inst->U.I.SrcReg[0].Swizzle, 3));

	inst_mul = rc_insert_new_instruction(&compiler->Base, inst->Prev);
	inst_mul->U.I.Opcode = RC_OPCODE_MUL;
	inst_mul->U.I.DstReg.File = RC_FILE_TEMPORARY;
	inst_mul->U.I.DstReg.Index = temp;
	inst_mul->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
	inst_mul->U.I.SrcReg[1].File = RC_FILE_TEMPORARY;
	inst_mul->U.I.SrcReg[1].Index = temp;
	inst_mul->U.I.SrcReg[1].Swizzle = RC_SWIZZLE_WWWW;

	reset_srcreg(&inst->U.I.SrcReg[0]);
	inst->U.I.Opcode = RC_OPCODE_TEX;
	inst->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
	inst->U.I.SrcReg[0].Index = temp;
}

/**
 * Transform TEX, TXP, TXB, and KIL instructions in the following ways:
 *  - implement texture compare (shadow extensions)
 *  - extract non-native source / destination operands
 *  - premultiply texture coordinates for RECT
 *  - extract operand swizzles
 *  - introduce a temporary register when write masks are needed
 */
int radeonTransformTEX(
	struct radeon_compiler * c,
	struct rc_instruction * inst,
	void* data)
{
	struct r300_fragment_program_compiler *compiler =
		(struct r300_fragment_program_compiler*)data;

	if (inst->U.I.Opcode != RC_OPCODE_TEX &&
		inst->U.I.Opcode != RC_OPCODE_TXB &&
		inst->U.I.Opcode != RC_OPCODE_TXP &&
		inst->U.I.Opcode != RC_OPCODE_KIL)
		return 0;

	/* ARB_shadow & EXT_shadow_funcs */
	if (inst->U.I.Opcode != RC_OPCODE_KIL &&
		((c->Program.ShadowSamplers & (1 << inst->U.I.TexSrcUnit)) ||
		 (compiler->state.unit[inst->U.I.TexSrcUnit].compare_mode_enabled))) {
		rc_compare_func comparefunc = compiler->state.unit[inst->U.I.TexSrcUnit].texture_compare_func;

		if (comparefunc == RC_COMPARE_FUNC_NEVER || comparefunc == RC_COMPARE_FUNC_ALWAYS) {
			inst->U.I.Opcode = RC_OPCODE_MOV;

			if (comparefunc == RC_COMPARE_FUNC_ALWAYS) {
				inst->U.I.SrcReg[0].File = RC_FILE_NONE;
				inst->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_1111;
			} else {
				inst->U.I.SrcReg[0] = shadow_ambient(compiler, inst->U.I.TexSrcUnit);
			}

			return 1;
		} else {
			rc_compare_func comparefunc = compiler->state.unit[inst->U.I.TexSrcUnit].texture_compare_func;
			struct rc_instruction * inst_rcp = NULL;
			struct rc_instruction * inst_mad;
			struct rc_instruction * inst_cmp;
			unsigned tmp_texsample;
			unsigned tmp_sum;
			unsigned tmp_recip_w = 0;
			int pass, fail, tex;

			/* Save the output register. */
			struct rc_dst_register output_reg = inst->U.I.DstReg;

			/* Redirect TEX to a new temp. */
			tmp_texsample = rc_find_free_temporary(c);
			inst->U.I.DstReg.File = RC_FILE_TEMPORARY;
			inst->U.I.DstReg.Index = tmp_texsample;
			inst->U.I.DstReg.WriteMask = RC_MASK_XYZW;

			if (inst->U.I.Opcode == RC_OPCODE_TXP) {
				tmp_recip_w = rc_find_free_temporary(c);

				/* Compute 1/W. */
				inst_rcp = rc_insert_new_instruction(c, inst);
				inst_rcp->U.I.Opcode = RC_OPCODE_RCP;
				inst_rcp->U.I.DstReg.File = RC_FILE_TEMPORARY;
				inst_rcp->U.I.DstReg.Index = tmp_recip_w;
				inst_rcp->U.I.DstReg.WriteMask = RC_MASK_W;
				inst_rcp->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
				inst_rcp->U.I.SrcReg[0].Swizzle =
					RC_MAKE_SWIZZLE_SMEAR(GET_SWZ(inst->U.I.SrcReg[0].Swizzle, 3));
			}

			/* Perspective-divide Z by W (if it's TXP) and add the texture sample (see below). */
			tmp_sum = rc_find_free_temporary(c);
			inst_mad = rc_insert_new_instruction(c, inst_rcp ? inst_rcp : inst);
			inst_mad->U.I.DstReg.File = RC_FILE_TEMPORARY;
			inst_mad->U.I.DstReg.Index = tmp_sum;
			inst_mad->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
			inst_mad->U.I.SrcReg[0].Swizzle =
				RC_MAKE_SWIZZLE_SMEAR(GET_SWZ(inst->U.I.SrcReg[0].Swizzle, 2));
			if (inst->U.I.Opcode == RC_OPCODE_TXP) {
				inst_mad->U.I.Opcode = RC_OPCODE_MAD;
				inst_mad->U.I.SrcReg[1].File = RC_FILE_TEMPORARY;
				inst_mad->U.I.SrcReg[1].Index = tmp_recip_w;
				inst_mad->U.I.SrcReg[1].Swizzle = RC_SWIZZLE_WWWW;
				tex = 2;
			} else {
				inst_mad->U.I.Opcode = RC_OPCODE_ADD;
				tex = 1;
			}
			inst_mad->U.I.SrcReg[tex].File = RC_FILE_TEMPORARY;
			inst_mad->U.I.SrcReg[tex].Index = tmp_texsample;
			inst_mad->U.I.SrcReg[tex].Swizzle = compiler->state.unit[inst->U.I.TexSrcUnit].depth_texture_swizzle;

			/* Fake EQUAL/NOTEQUAL, it seems to pass some tests suprisingly. */
			if (comparefunc == RC_COMPARE_FUNC_EQUAL) {
				comparefunc = RC_COMPARE_FUNC_GEQUAL;
			} else if (comparefunc == RC_COMPARE_FUNC_NOTEQUAL) {
				comparefunc = RC_COMPARE_FUNC_LESS;
			}

			/* Recall that SrcReg[0] is r, SrcReg[tex] is tex and:
			 *   LESS:    r  < tex  <=>      -tex+r < 0
			 *   GEQUAL:  r >= tex  <=> not (-tex+r < 0)
			 *   GREATER: r  > tex  <=>       tex-r < 0
			 *   LEQUAL:  r <= tex  <=> not ( tex-r < 0)
			 *
			 * This negates either r or tex: */
			if (comparefunc == RC_COMPARE_FUNC_LESS || comparefunc == RC_COMPARE_FUNC_GEQUAL)
				inst_mad->U.I.SrcReg[tex].Negate = inst_mad->U.I.SrcReg[tex].Negate ^ RC_MASK_XYZW;
			else
				inst_mad->U.I.SrcReg[0].Negate = inst_mad->U.I.SrcReg[0].Negate ^ RC_MASK_XYZW;

			/* This negates the whole expresion: */
			if (comparefunc == RC_COMPARE_FUNC_LESS || comparefunc == RC_COMPARE_FUNC_GREATER) {
				pass = 1;
				fail = 2;
			} else {
				pass = 2;
				fail = 1;
			}

			inst_cmp = rc_insert_new_instruction(c, inst_mad);
			inst_cmp->U.I.Opcode = RC_OPCODE_CMP;
			inst_cmp->U.I.DstReg = output_reg;
			inst_cmp->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
			inst_cmp->U.I.SrcReg[0].Index = tmp_sum;
			inst_cmp->U.I.SrcReg[pass].File = RC_FILE_NONE;
			inst_cmp->U.I.SrcReg[pass].Swizzle = RC_SWIZZLE_1111;
			inst_cmp->U.I.SrcReg[fail] = shadow_ambient(compiler, inst->U.I.TexSrcUnit);

			assert(tmp_texsample != tmp_sum && tmp_sum != tmp_recip_w);
		}
	}

	/* Divide by W if needed. */
	if (inst->U.I.Opcode == RC_OPCODE_TXP &&
	    (compiler->state.unit[inst->U.I.TexSrcUnit].wrap_mode == RC_WRAP_REPEAT ||
             compiler->state.unit[inst->U.I.TexSrcUnit].wrap_mode == RC_WRAP_MIRRORED_REPEAT)) {
		projective_divide(compiler, inst);
	}

	/* Texture wrap modes don't work on NPOT textures or texrects.
	 *
	 * The game plan is simple. We have two flags, fake_npot and
	 * non_normalized_coords, as well as a tex target. The RECT tex target
	 * will make the emitted code use non-scaled texcoords.
	 *
	 * Non-wrapped/clamped texcoords with NPOT are free in HW. Repeat and
	 * mirroring are not. If we need to repeat, we do:
	 *
	 * MUL temp, texcoord, <scaling factor constant>
	 * FRC temp, temp ; Discard integer portion of coords
	 *
	 * This gives us coords in [0, 1].
	 *
	 * Mirroring is trickier. We're going to start out like repeat:
	 *
	 * MUL temp, texcoord, <scaling factor constant> ; De-mirror across axes
	 * MUL temp, temp, 0.5 ; Pattern repeats in [0, 2]
	 *                            ; so scale to [0, 1]
	 * FRC temp, temp ; Make the pattern repeat
	 * MAD temp, temp, 2, -1 ; Move the pattern to [-1, 1]
	 * ADD temp, 1, -abs(temp) ; Now comes a neat trick: use abs to mirror the pattern.
	 *				; The pattern is backwards, so reverse it (1-x).
	 *
	 * This gives us coords in [0, 1].
	 *
	 * ~ C & M. ;)
	 */
	if (inst->U.I.Opcode != RC_OPCODE_KIL &&
		(inst->U.I.TexSrcTarget == RC_TEXTURE_RECT ||
			compiler->state.unit[inst->U.I.TexSrcUnit].fake_npot ||
			compiler->state.unit[inst->U.I.TexSrcUnit].non_normalized_coords)) {
		rc_wrap_mode wrapmode = compiler->state.unit[inst->U.I.TexSrcUnit].wrap_mode;

		/* R300 cannot sample from rectangles. */
		if (!c->is_r500) {
			lower_texture_rect(compiler, inst);
		}

		if (compiler->state.unit[inst->U.I.TexSrcUnit].fake_npot &&
			wrapmode != RC_WRAP_NONE) {
			struct rc_instruction *inst_mov;
			unsigned temp = rc_find_free_temporary(c);

			/* For NPOT fallback, we need normalized coordinates anyway. */
			if (c->is_r500) {
				lower_texture_rect(compiler, inst);
			}

			if (wrapmode == RC_WRAP_REPEAT) {
				/* Both instructions will be paired up. */
				struct rc_instruction *inst_frc = rc_insert_new_instruction(c, inst->Prev);

				inst_frc->U.I.Opcode = RC_OPCODE_FRC;
				inst_frc->U.I.DstReg.File = RC_FILE_TEMPORARY;
				inst_frc->U.I.DstReg.Index = temp;
				inst_frc->U.I.DstReg.WriteMask = RC_MASK_XYZ;
				inst_frc->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
			} else if (wrapmode == RC_WRAP_MIRRORED_REPEAT) {
				/*
				 * Function:
				 *   f(v) = 1 - abs(frac(v * 0.5) * 2 - 1)
				 *
				 * Code:
				 *   MUL temp, src0, 0.5
				 *   FRC temp, temp
				 *   MAD temp, temp, 2, -1
				 *   ADD temp, 1, -abs(temp)
				 */

				struct rc_instruction *inst_mul, *inst_frc, *inst_mad, *inst_add;
				unsigned two, two_swizzle;

				inst_mul = rc_insert_new_instruction(c, inst->Prev);

				inst_mul->U.I.Opcode = RC_OPCODE_MUL;
				inst_mul->U.I.DstReg.File = RC_FILE_TEMPORARY;
				inst_mul->U.I.DstReg.Index = temp;
				inst_mul->U.I.DstReg.WriteMask = RC_MASK_XYZ;
				inst_mul->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
				inst_mul->U.I.SrcReg[1].Swizzle = RC_SWIZZLE_HHHH;

				inst_frc = rc_insert_new_instruction(c, inst->Prev);

				inst_frc->U.I.Opcode = RC_OPCODE_FRC;
				inst_frc->U.I.DstReg.File = RC_FILE_TEMPORARY;
				inst_frc->U.I.DstReg.Index = temp;
				inst_frc->U.I.DstReg.WriteMask = RC_MASK_XYZ;
				inst_frc->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
				inst_frc->U.I.SrcReg[0].Index = temp;
				inst_frc->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_XYZ0;

				two = rc_constants_add_immediate_scalar(&c->Program.Constants, 2, &two_swizzle);
				inst_mad = rc_insert_new_instruction(c, inst->Prev);

				inst_mad->U.I.Opcode = RC_OPCODE_MAD;
				inst_mad->U.I.DstReg.File = RC_FILE_TEMPORARY;
				inst_mad->U.I.DstReg.Index = temp;
				inst_mad->U.I.DstReg.WriteMask = RC_MASK_XYZ;
				inst_mad->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
				inst_mad->U.I.SrcReg[0].Index = temp;
				inst_mad->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_XYZ0;
				inst_mad->U.I.SrcReg[1].File = RC_FILE_CONSTANT;
				inst_mad->U.I.SrcReg[1].Index = two;
				inst_mad->U.I.SrcReg[1].Swizzle = two_swizzle;
				inst_mad->U.I.SrcReg[2].Swizzle = RC_SWIZZLE_1111;
				inst_mad->U.I.SrcReg[2].Negate = RC_MASK_XYZ;

				inst_add = rc_insert_new_instruction(c, inst->Prev);

				inst_add->U.I.Opcode = RC_OPCODE_ADD;
				inst_add->U.I.DstReg.File = RC_FILE_TEMPORARY;
				inst_add->U.I.DstReg.Index = temp;
				inst_add->U.I.DstReg.WriteMask = RC_MASK_XYZ;
				inst_add->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_1111;
				inst_add->U.I.SrcReg[1].File = RC_FILE_TEMPORARY;
				inst_add->U.I.SrcReg[1].Index = temp;
				inst_add->U.I.SrcReg[1].Swizzle = RC_SWIZZLE_XYZ0;
				inst_add->U.I.SrcReg[1].Abs = 1;
				inst_add->U.I.SrcReg[1].Negate = RC_MASK_XYZ;
			} else if (wrapmode == RC_WRAP_MIRRORED_CLAMP) {
				/*
				 * Mirrored clamp modes are bloody simple, we just use abs
				 * to mirror [0, 1] into [-1, 0]. This works for
				 * all modes i.e. CLAMP, CLAMP_TO_EDGE, and CLAMP_TO_BORDER.
				 */
				struct rc_instruction *inst_mov;

				inst_mov = rc_insert_new_instruction(c, inst->Prev);

				inst_mov->U.I.Opcode = RC_OPCODE_MOV;
				inst_mov->U.I.DstReg.File = RC_FILE_TEMPORARY;
				inst_mov->U.I.DstReg.Index = temp;
				inst_mov->U.I.DstReg.WriteMask = RC_MASK_XYZ;
				inst_mov->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
				inst_mov->U.I.SrcReg[0].Abs = 1;
			}

			/* Preserve W for TXP/TXB. */
			inst_mov = rc_insert_new_instruction(c, inst->Prev);

			inst_mov->U.I.Opcode = RC_OPCODE_MOV;
			inst_mov->U.I.DstReg.File = RC_FILE_TEMPORARY;
			inst_mov->U.I.DstReg.Index = temp;
			inst_mov->U.I.DstReg.WriteMask = RC_MASK_W;
			inst_mov->U.I.SrcReg[0] = inst->U.I.SrcReg[0];

			reset_srcreg(&inst->U.I.SrcReg[0]);
			inst->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
			inst->U.I.SrcReg[0].Index = temp;
		}
	}

	/* Cannot write texture to output registers (all chips) or with masks (non-r500) */
	if (inst->U.I.Opcode != RC_OPCODE_KIL &&
		(inst->U.I.DstReg.File != RC_FILE_TEMPORARY ||
		 (!c->is_r500 && inst->U.I.DstReg.WriteMask != RC_MASK_XYZW))) {
		struct rc_instruction * inst_mov = rc_insert_new_instruction(c, inst);

		inst_mov->U.I.Opcode = RC_OPCODE_MOV;
		inst_mov->U.I.DstReg = inst->U.I.DstReg;
		inst_mov->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
		inst_mov->U.I.SrcReg[0].Index = rc_find_free_temporary(c);

		inst->U.I.DstReg.File = RC_FILE_TEMPORARY;
		inst->U.I.DstReg.Index = inst_mov->U.I.SrcReg[0].Index;
		inst->U.I.DstReg.WriteMask = RC_MASK_XYZW;
	}

	/* Cannot read texture coordinate from constants file */
	if (inst->U.I.SrcReg[0].File != RC_FILE_TEMPORARY && inst->U.I.SrcReg[0].File != RC_FILE_INPUT) {
		struct rc_instruction * inst_mov = rc_insert_new_instruction(c, inst->Prev);

		inst_mov->U.I.Opcode = RC_OPCODE_MOV;
		inst_mov->U.I.DstReg.File = RC_FILE_TEMPORARY;
		inst_mov->U.I.DstReg.Index = rc_find_free_temporary(c);
		inst_mov->U.I.SrcReg[0] = inst->U.I.SrcReg[0];

		reset_srcreg(&inst->U.I.SrcReg[0]);
		inst->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
		inst->U.I.SrcReg[0].Index = inst_mov->U.I.DstReg.Index;
	}

	return 1;
}
