mirror of
https://github.com/libretro/scummvm.git
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225 lines
6.5 KiB
C++
225 lines
6.5 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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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, either version 3 of the License, or
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* (at your option) any later version.
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*
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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 for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "graphics/tinygl/gl.h"
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#include "graphics/tinygl/zgl.h"
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#include "graphics/tinygl/zbuffer.h"
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#include "graphics/tinygl/texelbuffer.h"
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namespace TinyGL {
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#define ZB_POINT_ST_UNIT (1 << ZB_POINT_ST_FRAC_BITS)
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#define ZB_POINT_ST_FRAC_MASK (ZB_POINT_ST_UNIT - 1)
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TexelBuffer::TexelBuffer(uint width, uint height, uint textureSize) {
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assert(width);
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assert(height);
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assert(textureSize);
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_width = width;
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_height = height;
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_fracTextureUnit = textureSize << ZB_POINT_ST_FRAC_BITS;
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_fracTextureMask = _fracTextureUnit - 1;
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_widthRatio = (float) width / textureSize;
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_heightRatio = (float) height / textureSize;
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}
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static inline uint wrap(uint wrap_mode, int coord, uint _fracTextureUnit, uint _fracTextureMask) {
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switch (wrap_mode) {
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case TGL_MIRRORED_REPEAT:
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if (coord & _fracTextureUnit)
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return _fracTextureMask - (coord & _fracTextureMask);
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return coord & _fracTextureMask;
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case TGL_CLAMP_TO_EDGE:
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if (coord < 0)
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return 0;
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if ((uint) coord > _fracTextureMask)
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return _fracTextureMask;
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return coord;
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default:
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// Fall through
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case TGL_REPEAT:
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return coord & _fracTextureMask;
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}
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}
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void TexelBuffer::getARGBAt(
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uint wrap_s, uint wrap_t,
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int s, int t,
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uint8 &a, uint8 &r, uint8 &g, uint8 &b
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) const {
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uint x, y;
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x = wrap(wrap_s, s, _fracTextureUnit, _fracTextureMask) * _widthRatio;
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y = wrap(wrap_t, t, _fracTextureUnit, _fracTextureMask) * _heightRatio;
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getARGBAt(
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(x >> ZB_POINT_ST_FRAC_BITS) + (y >> ZB_POINT_ST_FRAC_BITS) * _width,
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x & ZB_POINT_ST_FRAC_MASK, y & ZB_POINT_ST_FRAC_MASK,
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a, r, g, b
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);
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}
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// Nearest: store texture in original size.
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NearestTexelBuffer::NearestTexelBuffer(const Graphics::PixelBuffer &buf, uint width, uint height, uint textureSize) : TexelBuffer(width, height, textureSize) {
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uint pixel_count = _width * _height;
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_buf = Graphics::PixelBuffer(buf.getFormat(), pixel_count, DisposeAfterUse::NO);
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_buf.copyBuffer(0, pixel_count, buf);
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}
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NearestTexelBuffer::~NearestTexelBuffer() {
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_buf.free();
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}
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void NearestTexelBuffer::getARGBAt(
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uint pixel,
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uint, uint,
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uint8 &a, uint8 &r, uint8 &g, uint8 &b
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) const {
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_buf.getARGBAt(pixel, a, r, g, b);
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}
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// Bilinear: each texture coordinates corresponds to the 4 original image
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// pixels linear interpolation has to work on, so that they are near each
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// other in CPU data cache, and a single actual memory fetch happens. This
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// allows applying linear filtering at render time at a very low performance
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// cost. As we expect to work on small-ish textures (512*512 ?) the 4x memory
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// usage increase should be negligible.
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#define A_OFFSET (0 * 4)
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#define R_OFFSET (1 * 4)
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#define G_OFFSET (2 * 4)
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#define B_OFFSET (3 * 4)
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#define P00_OFFSET 0
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#define P01_OFFSET 1
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#define P10_OFFSET 2
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#define P11_OFFSET 3
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#define PIXEL_PER_TEXEL_SHIFT 2
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BilinearTexelBuffer::BilinearTexelBuffer(const Graphics::PixelBuffer &buf, uint width, uint height, uint textureSize) : TexelBuffer(width, height, textureSize) {
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uint pixel00_offset = 0, pixel11_offset, pixel01_offset, pixel10_offset;
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uint8 *texel8;
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uint32 *texel32;
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texel32 = _texels = new uint32[_width * _height << PIXEL_PER_TEXEL_SHIFT];
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for (uint y = 0; y < _height; y++) {
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for (uint x = 0; x < _width; x++) {
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texel8 = (uint8 *)texel32;
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pixel11_offset = pixel00_offset + _width + 1;
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buf.getARGBAt(
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pixel00_offset,
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*(texel8 + P00_OFFSET + A_OFFSET),
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*(texel8 + P00_OFFSET + R_OFFSET),
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*(texel8 + P00_OFFSET + G_OFFSET),
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*(texel8 + P00_OFFSET + B_OFFSET)
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);
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if ((x + 1) == _width) {
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pixel11_offset -= 1;
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pixel01_offset = pixel00_offset;
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} else
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pixel01_offset = pixel00_offset + 1;
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buf.getARGBAt(
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pixel01_offset,
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*(texel8 + P01_OFFSET + A_OFFSET),
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*(texel8 + P01_OFFSET + R_OFFSET),
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*(texel8 + P01_OFFSET + G_OFFSET),
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*(texel8 + P01_OFFSET + B_OFFSET)
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);
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if ((y + 1) == _height) {
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pixel11_offset -= _width;
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pixel10_offset = pixel00_offset;
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} else
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pixel10_offset = pixel00_offset + _width;
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buf.getARGBAt(
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pixel10_offset,
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*(texel8 + P10_OFFSET + A_OFFSET),
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*(texel8 + P10_OFFSET + R_OFFSET),
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*(texel8 + P10_OFFSET + G_OFFSET),
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*(texel8 + P10_OFFSET + B_OFFSET)
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);
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buf.getARGBAt(
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pixel11_offset,
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*(texel8 + P11_OFFSET + A_OFFSET),
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*(texel8 + P11_OFFSET + R_OFFSET),
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*(texel8 + P11_OFFSET + G_OFFSET),
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*(texel8 + P11_OFFSET + B_OFFSET)
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);
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texel32 += 1 << PIXEL_PER_TEXEL_SHIFT;
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pixel00_offset++;
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}
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}
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}
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BilinearTexelBuffer::~BilinearTexelBuffer() {
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delete[] _texels;
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}
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static inline int interpolate(int v00, int v01, int v10, int xf, int yf) {
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return v00 + (((v01 - v00) * xf + (v10 - v00) * yf) >> ZB_POINT_ST_FRAC_BITS);
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}
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void BilinearTexelBuffer::getARGBAt(
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uint pixel,
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uint ds, uint dt,
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uint8 &a, uint8 &r, uint8 &g, uint8 &b
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) const {
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uint p00_offset, p01_offset, p10_offset;
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uint8 *texel = (uint8 *)(_texels + (pixel << PIXEL_PER_TEXEL_SHIFT));
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if ((ds + dt) > ZB_POINT_ST_UNIT) {
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p00_offset = P11_OFFSET;
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p10_offset = P01_OFFSET;
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p01_offset = P10_OFFSET;
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ds = ZB_POINT_ST_UNIT - ds;
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dt = ZB_POINT_ST_UNIT - dt;
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} else {
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p00_offset = P00_OFFSET;
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p10_offset = P10_OFFSET;
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p01_offset = P01_OFFSET;
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}
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a = interpolate(
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*(texel + p00_offset + A_OFFSET),
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*(texel + p01_offset + A_OFFSET),
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*(texel + p10_offset + A_OFFSET),
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ds,
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dt
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);
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r = interpolate(
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*(texel + p00_offset + R_OFFSET),
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*(texel + p01_offset + R_OFFSET),
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*(texel + p10_offset + R_OFFSET),
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ds,
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dt
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);
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g = interpolate(
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*(texel + p00_offset + G_OFFSET),
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*(texel + p01_offset + G_OFFSET),
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*(texel + p10_offset + G_OFFSET),
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ds,
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dt
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);
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b = interpolate(
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*(texel + p00_offset + B_OFFSET),
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*(texel + p01_offset + B_OFFSET),
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*(texel + p10_offset + B_OFFSET),
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ds,
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dt
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);
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}
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} // end of namespace TinyGL
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