mirror of
https://github.com/libretro/ppsspp.git
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122 lines
3.7 KiB
C++
122 lines
3.7 KiB
C++
// Copyright (c) 2012- PPSSPP Project.
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, version 2.0 or later versions.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License 2.0 for more details.
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// A copy of the GPL 2.0 should have been included with the program.
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// If not, see http://www.gnu.org/licenses/
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// Official git repository and contact information can be found at
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// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
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#include "GPU/Common/TextureDecoder.h"
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// TODO: Move some common things into here.
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static inline u32 makecol(int r, int g, int b, int a) {
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return (a << 24) | (r << 16) | (g << 8) | b;
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}
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// This could probably be done faster by decoding two or four blocks at a time with SSE/NEON.
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void DecodeDXT1Block(u32 *dst, const DXT1Block *src, int pitch, bool ignore1bitAlpha) {
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// S3TC Decoder
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// Needs more speed and debugging.
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u16 c1 = (src->color1);
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u16 c2 = (src->color2);
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int red1 = Convert5To8(c1 & 0x1F);
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int red2 = Convert5To8(c2 & 0x1F);
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int green1 = Convert6To8((c1 >> 5) & 0x3F);
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int green2 = Convert6To8((c2 >> 5) & 0x3F);
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int blue1 = Convert5To8((c1 >> 11) & 0x1F);
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int blue2 = Convert5To8((c2 >> 11) & 0x1F);
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u32 colors[4];
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colors[0] = makecol(red1, green1, blue1, 255);
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colors[1] = makecol(red2, green2, blue2, 255);
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if (c1 > c2 || ignore1bitAlpha) {
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int blue3 = ((blue2 - blue1) >> 1) - ((blue2 - blue1) >> 3);
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int green3 = ((green2 - green1) >> 1) - ((green2 - green1) >> 3);
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int red3 = ((red2 - red1) >> 1) - ((red2 - red1) >> 3);
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colors[2] = makecol(red1 + red3, green1 + green3, blue1 + blue3, 255);
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colors[3] = makecol(red2 - red3, green2 - green3, blue2 - blue3, 255);
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} else {
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colors[2] = makecol((red1 + red2 + 1) / 2, // Average
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(green1 + green2 + 1) / 2,
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(blue1 + blue2 + 1) / 2, 255);
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colors[3] = makecol(red2, green2, blue2, 0); // Color2 but transparent
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}
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for (int y = 0; y < 4; y++) {
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int val = src->lines[y];
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for (int x = 0; x < 4; x++) {
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dst[x] = colors[val & 3];
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val >>= 2;
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}
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dst += pitch;
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}
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}
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void DecodeDXT3Block(u32 *dst, const DXT3Block *src, int pitch)
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{
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DecodeDXT1Block(dst, &src->color, pitch, true);
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for (int y = 0; y < 4; y++) {
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u32 line = src->alphaLines[y];
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for (int x = 0; x < 4; x++) {
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const u8 a4 = line & 0xF;
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dst[x] = (dst[x] & 0xFFFFFF) | (a4 << 24) | (a4 << 28);
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line >>= 4;
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}
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dst += pitch;
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}
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}
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static inline u8 lerp8(const DXT5Block *src, int n) {
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float d = n / 7.0f;
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return (u8)(src->alpha1 + (src->alpha2 - src->alpha1) * d);
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}
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static inline u8 lerp6(const DXT5Block *src, int n) {
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float d = n / 5.0f;
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return (u8)(src->alpha1 + (src->alpha2 - src->alpha1) * d);
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}
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// The alpha channel is not 100% correct
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void DecodeDXT5Block(u32 *dst, const DXT5Block *src, int pitch) {
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DecodeDXT1Block(dst, &src->color, pitch, true);
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u8 alpha[8];
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alpha[0] = src->alpha1;
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alpha[1] = src->alpha2;
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if (alpha[0] > alpha[1]) {
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alpha[2] = lerp8(src, 1);
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alpha[3] = lerp8(src, 2);
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alpha[4] = lerp8(src, 3);
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alpha[5] = lerp8(src, 4);
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alpha[6] = lerp8(src, 5);
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alpha[7] = lerp8(src, 6);
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} else {
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alpha[2] = lerp6(src, 1);
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alpha[3] = lerp6(src, 2);
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alpha[4] = lerp6(src, 3);
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alpha[5] = lerp6(src, 4);
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alpha[6] = 0;
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alpha[7] = 255;
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}
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u64 data = ((u64)(u16)src->alphadata1 << 32) | (u32)src->alphadata2;
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for (int y = 0; y < 4; y++) {
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for (int x = 0; x < 4; x++) {
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dst[x] = (dst[x] & 0xFFFFFF) | (alpha[data & 7] << 24);
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data >>= 3;
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}
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dst += pitch;
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}
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} |