270 lines
8.2 KiB
C++
270 lines
8.2 KiB
C++
// basisu_pvrtc1_4.cpp
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// Copyright (C) 2019 Binomial LLC. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "basisu_pvrtc1_4.h"
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namespace basisu
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{
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uint32_t pvrtc4_swizzle_uv(uint32_t width, uint32_t height, uint32_t x, uint32_t y)
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{
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assert((x < width) && (y < height) && basisu::is_pow2(height) && basisu::is_pow2(width));
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uint32_t min_d = width, max_v = y;
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if (height < width)
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{
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min_d = height;
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max_v = x;
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}
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// Interleave the XY LSB's
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uint32_t shift_ofs = 0, swizzled = 0;
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for (uint32_t s_bit = 1, d_bit = 1; s_bit < min_d; s_bit <<= 1, d_bit <<= 2, ++shift_ofs)
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{
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if (y & s_bit) swizzled |= d_bit;
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if (x & s_bit) swizzled |= (2 * d_bit);
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}
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max_v >>= shift_ofs;
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// OR in the rest of the bits from the largest dimension
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swizzled |= (max_v << (2 * shift_ofs));
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return swizzled;
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}
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color_rgba pvrtc4_block::get_endpoint(uint32_t endpoint_index, bool unpack) const
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{
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assert(endpoint_index < 2);
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const uint32_t packed = m_endpoints >> (endpoint_index * 16);
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uint32_t r, g, b, a;
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if (packed & 0x8000)
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{
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// opaque 554 or 555
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if (!endpoint_index)
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{
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r = (packed >> 10) & 31;
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g = (packed >> 5) & 31;
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b = (packed >> 1) & 15;
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if (unpack)
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{
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b = (b << 1) | (b >> 3);
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}
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}
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else
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{
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r = (packed >> 10) & 31;
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g = (packed >> 5) & 31;
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b = packed & 31;
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}
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a = unpack ? 255 : 7;
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}
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else
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{
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// translucent 4433 or 4443
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if (!endpoint_index)
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{
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a = (packed >> 12) & 7;
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r = (packed >> 8) & 15;
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g = (packed >> 4) & 15;
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b = (packed >> 1) & 7;
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if (unpack)
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{
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a = (a << 1);
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a = (a << 4) | a;
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r = (r << 1) | (r >> 3);
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g = (g << 1) | (g >> 3);
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b = (b << 2) | (b >> 1);
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}
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}
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else
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{
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a = (packed >> 12) & 7;
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r = (packed >> 8) & 15;
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g = (packed >> 4) & 15;
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b = packed & 15;
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if (unpack)
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{
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a = (a << 1);
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a = (a << 4) | a;
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r = (r << 1) | (r >> 3);
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g = (g << 1) | (g >> 3);
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b = (b << 1) | (b >> 3);
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}
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}
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}
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if (unpack)
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{
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r = (r << 3) | (r >> 2);
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g = (g << 3) | (g >> 2);
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b = (b << 3) | (b >> 2);
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}
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assert((r < 256) && (g < 256) && (b < 256) && (a < 256));
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return color_rgba(r, g, b, a);
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}
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color_rgba pvrtc4_block::get_endpoint_5554(uint32_t endpoint_index) const
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{
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assert(endpoint_index < 2);
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const uint32_t packed = m_endpoints >> (endpoint_index * 16);
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uint32_t r, g, b, a;
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if (packed & 0x8000)
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{
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// opaque 554 or 555
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if (!endpoint_index)
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{
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r = (packed >> 10) & 31;
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g = (packed >> 5) & 31;
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b = (packed >> 1) & 15;
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b = (b << 1) | (b >> 3);
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}
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else
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{
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r = (packed >> 10) & 31;
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g = (packed >> 5) & 31;
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b = packed & 31;
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}
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a = 15;
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}
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else
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{
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// translucent 4433 or 4443
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if (!endpoint_index)
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{
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a = (packed >> 12) & 7;
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r = (packed >> 8) & 15;
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g = (packed >> 4) & 15;
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b = (packed >> 1) & 7;
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a = a << 1;
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r = (r << 1) | (r >> 3);
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g = (g << 1) | (g >> 3);
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b = (b << 2) | (b >> 1);
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}
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else
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{
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a = (packed >> 12) & 7;
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r = (packed >> 8) & 15;
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g = (packed >> 4) & 15;
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b = packed & 15;
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a = a << 1;
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r = (r << 1) | (r >> 3);
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g = (g << 1) | (g >> 3);
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b = (b << 1) | (b >> 3);
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}
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}
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assert((r < 32) && (g < 32) && (b < 32) && (a < 16));
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return color_rgba(r, g, b, a);
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}
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bool pvrtc4_image::get_interpolated_colors(uint32_t x, uint32_t y, color_rgba* pColors) const
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{
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assert((x < m_width) && (y < m_height));
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int block_x0 = (static_cast<int>(x) - 2) >> 2;
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int block_x1 = block_x0 + 1;
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int block_y0 = (static_cast<int>(y) - 2) >> 2;
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int block_y1 = block_y0 + 1;
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block_x0 = posmod(block_x0, m_block_width);
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block_x1 = posmod(block_x1, m_block_width);
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block_y0 = posmod(block_y0, m_block_height);
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block_y1 = posmod(block_y1, m_block_height);
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pColors[0] = interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(0), m_blocks(block_x1, block_y0).get_endpoint_5554(0), m_blocks(block_x0, block_y1).get_endpoint_5554(0), m_blocks(block_x1, block_y1).get_endpoint_5554(0));
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pColors[3] = interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(1), m_blocks(block_x1, block_y0).get_endpoint_5554(1), m_blocks(block_x0, block_y1).get_endpoint_5554(1), m_blocks(block_x1, block_y1).get_endpoint_5554(1));
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if (get_block_uses_transparent_modulation(x >> 2, y >> 2))
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{
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for (uint32_t c = 0; c < 4; c++)
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{
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uint32_t m = (pColors[0][c] + pColors[3][c]) / 2;
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pColors[1][c] = static_cast<uint8_t>(m);
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pColors[2][c] = static_cast<uint8_t>(m);
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}
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pColors[2][3] = 0;
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return true;
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}
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for (uint32_t c = 0; c < 4; c++)
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{
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pColors[1][c] = static_cast<uint8_t>((pColors[0][c] * 5 + pColors[3][c] * 3) / 8);
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pColors[2][c] = static_cast<uint8_t>((pColors[0][c] * 3 + pColors[3][c] * 5) / 8);
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}
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return false;
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}
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color_rgba pvrtc4_image::get_pixel(uint32_t x, uint32_t y, uint32_t m) const
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{
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assert((x < m_width) && (y < m_height));
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int block_x0 = (static_cast<int>(x) - 2) >> 2;
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int block_x1 = block_x0 + 1;
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int block_y0 = (static_cast<int>(y) - 2) >> 2;
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int block_y1 = block_y0 + 1;
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block_x0 = posmod(block_x0, m_block_width);
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block_x1 = posmod(block_x1, m_block_width);
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block_y0 = posmod(block_y0, m_block_height);
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block_y1 = posmod(block_y1, m_block_height);
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if (get_block_uses_transparent_modulation(x >> 2, y >> 2))
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{
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if (m == 0)
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return interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(0), m_blocks(block_x1, block_y0).get_endpoint_5554(0), m_blocks(block_x0, block_y1).get_endpoint_5554(0), m_blocks(block_x1, block_y1).get_endpoint_5554(0));
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else if (m == 3)
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return interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(1), m_blocks(block_x1, block_y0).get_endpoint_5554(1), m_blocks(block_x0, block_y1).get_endpoint_5554(1), m_blocks(block_x1, block_y1).get_endpoint_5554(1));
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color_rgba l(interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(0), m_blocks(block_x1, block_y0).get_endpoint_5554(0), m_blocks(block_x0, block_y1).get_endpoint_5554(0), m_blocks(block_x1, block_y1).get_endpoint_5554(0)));
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color_rgba h(interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(1), m_blocks(block_x1, block_y0).get_endpoint_5554(1), m_blocks(block_x0, block_y1).get_endpoint_5554(1), m_blocks(block_x1, block_y1).get_endpoint_5554(1)));
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return color_rgba((l[0] + h[0]) / 2, (l[1] + h[1]) / 2, (l[2] + h[2]) / 2, (m == 2) ? 0 : (l[3] + h[3]) / 2);
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}
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else
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{
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if (m == 0)
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return interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(0), m_blocks(block_x1, block_y0).get_endpoint_5554(0), m_blocks(block_x0, block_y1).get_endpoint_5554(0), m_blocks(block_x1, block_y1).get_endpoint_5554(0));
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else if (m == 3)
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return interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(1), m_blocks(block_x1, block_y0).get_endpoint_5554(1), m_blocks(block_x0, block_y1).get_endpoint_5554(1), m_blocks(block_x1, block_y1).get_endpoint_5554(1));
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color_rgba l(interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(0), m_blocks(block_x1, block_y0).get_endpoint_5554(0), m_blocks(block_x0, block_y1).get_endpoint_5554(0), m_blocks(block_x1, block_y1).get_endpoint_5554(0)));
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color_rgba h(interpolate(x, y, m_blocks(block_x0, block_y0).get_endpoint_5554(1), m_blocks(block_x1, block_y0).get_endpoint_5554(1), m_blocks(block_x0, block_y1).get_endpoint_5554(1), m_blocks(block_x1, block_y1).get_endpoint_5554(1)));
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if (m == 2)
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return color_rgba((l[0] * 3 + h[0] * 5) / 8, (l[1] * 3 + h[1] * 5) / 8, (l[2] * 3 + h[2] * 5) / 8, (l[3] * 3 + h[3] * 5) / 8);
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else
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return color_rgba((l[0] * 5 + h[0] * 3) / 8, (l[1] * 5 + h[1] * 3) / 8, (l[2] * 5 + h[2] * 3) / 8, (l[3] * 5 + h[3] * 3) / 8);
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}
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}
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} // basisu
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