131 lines
4.1 KiB
Lua
131 lines
4.1 KiB
Lua
dofile("init.lua")
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-- encode a bitmap
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local _ = { 0, 0, 0 }
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local R = { 255, 127, 127 }
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local pixels = {
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{ _, _, _, _, _, _, _ },
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{ _, _, _, R, _, _, _ },
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{ _, _, R, R, R, _, _ },
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{ _, R, R, R, R, R, _ },
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{ _, R, R, R, R, R, _ },
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{ _, _, R, _, R, _, _ },
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{ _, _, _, _, _, _, _ },
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}
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tga_encoder.image(pixels):save("bitmap_small.tga")
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-- change a single pixel, then rescale the bitmap
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local pixels_orig = pixels
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pixels_orig[4][4] = { 255, 255, 255 }
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local pixels = {}
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for x = 1,56,1 do
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local x_orig = math.ceil(x/8)
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for z = 1,56,1 do
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local z_orig = math.ceil(z/8)
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local color = pixels_orig[z_orig][x_orig]
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pixels[z] = pixels[z] or {}
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pixels[z][x] = color
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end
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end
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tga_encoder.image(pixels):save("bitmap_large.tga")
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-- note that the uncompressed grayscale TGA file written in this
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-- example is 80 bytes – but an optimized PNG file is 81 bytes …
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local pixels = {}
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for x = 1,6,1 do -- left to right
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for z = 1,6,1 do -- bottom to top
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local color = { math.min(x * z * 4 - 1, 255) }
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pixels[z] = pixels[z] or {}
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pixels[z][x] = color
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end
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end
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tga_encoder.image(pixels):save("gradient_8bpp_raw.tga", {color_format="Y8", compression="RAW"})
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local pixels = {}
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for x = 1,16,1 do -- left to right
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for z = 1,16,1 do -- bottom to top
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local r = math.min(x * 32 - 1, 255)
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local g = math.min(z * 32 - 1, 255)
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local b = 0
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-- blue rectangle in top right corner
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if x > 8 and z > 8 then
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r = 0
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g = 0
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b = math.min(z * 16 - 1, 255)
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end
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local color = { r, g, b }
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pixels[z] = pixels[z] or {}
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pixels[z][x] = color
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end
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end
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local gradients = tga_encoder.image(pixels)
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gradients:save("gradients_8bpp_raw.tga", {color_format="Y8", compression="RAW"})
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gradients:save("gradients_16bpp_raw.tga", {color_format="A1R5G5B5", compression="RAW"})
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gradients:save("gradients_16bpp_rle.tga", {color_format="A1R5G5B5", compression="RLE"})
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gradients:save("gradients_24bpp_raw.tga", {color_format="B8G8R8", compression="RAW"})
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gradients:save("gradients_24bpp_rle.tga", {color_format="B8G8R8", compression="RLE"})
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for x = 1,16,1 do -- left to right
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for z = 1,16,1 do -- bottom to top
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local color = pixels[z][x]
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color[#color+1] = ((x * x) + (z * z)) % 256
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pixels[z][x] = color
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end
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end
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gradients:save("gradients_32bpp_raw.tga", {color_format="B8G8R8A8", compression="RAW"})
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-- the RLE-compressed file is larger than just dumping pixels because
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-- the gradients in this picture can not be compressed well using RLE
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gradients:save("gradients_32bpp_rle.tga", {color_format="B8G8R8A8", compression="RLE"})
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local pixels = {}
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for x = 1,512,1 do -- left to right
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for z = 1,512,1 do -- bottom to top
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local oz = (z - 256) / 256 + 0.75
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local ox = (x - 256) / 256
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local px, pz, i = 0, 0, 0
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while (px * px) + (pz * pz) <= 4 and i < 128 do
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px = (px * px) - (pz * pz) + oz
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pz = (2 * px * pz) + ox
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i = i + 1
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end
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local color = {
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math.max(0, math.min(255, math.floor(px * 64))),
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math.max(0, math.min(255, math.floor(pz * 64))),
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math.max(0, math.min(255, math.floor(i))),
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}
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pixels[z] = pixels[z] or {}
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pixels[z][x] = color
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end
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end
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tga_encoder.image(pixels):save("fractal_8bpp.tga", {color_format="Y8"})
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tga_encoder.image(pixels):save("fractal_16bpp.tga", {color_format="A1R5G5B5"})
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tga_encoder.image(pixels):save("fractal_24bpp.tga", {color_format="B8G8R8"})
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-- encode a colormapped bitmap
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local K = { 0 }
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local B = { 1 }
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local R = { 2 }
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local G = { 3 }
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local W = { 4 }
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local colormap = {
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{ 1, 2, 3 }, -- K
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{ 0, 0, 255 }, -- B
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{ 255, 0, 0 }, -- R
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{ 0, 255, 0 }, -- G
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{ 253, 254, 255 }, -- W
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}
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local pixels = {
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{ W, K, W, K, W, K, W },
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{ R, G, B, R, G, B, K },
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{ K, W, K, W, K, W, K },
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{ G, B, R, G, B, R, W },
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{ W, W, W, K, K, K, W },
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{ B, R, G, B, R, G, K },
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{ B, R, G, B, R, G, W },
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}
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-- note that the uncompressed colormapped TGA file written in this
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-- example is 108 bytes – but an optimized PNG file is 121 bytes …
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tga_encoder.image(pixels):save("colormapped_B8G8R8.tga", {colormap=colormap})
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-- encoding as A1R5G5B5 saves 1 byte per palette entry → 103 bytes
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tga_encoder.image(pixels):save("colormapped_A1R5G5B5.tga", {colormap=colormap, color_format="A1R5G5B5"})
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