de5eb6562e
BmpHeader.ReadDims reads texture dims from the pre-converted BMP header (VM- thread-safe, no pixel decode) — the data source for GetTextureSize. `Age.Cli gfx <SCENE>` runs a scene and dumps set-texture/get-texture-size/draw-texture in order with resolved file + computed geometry, mirroring the `audio` diagnostic. Confirms 0x208 now yields real dims (800x600/800x800/800x227) and sane UI geometry; surfaces the first-load anchor edge (unseeded state, Phase B). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
26 lines
1018 B
C#
26 lines
1018 B
C#
namespace Age.Engine.Sys4;
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/// <summary>
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/// Reads pixel dimensions from a BMP file header (BITMAPINFOHEADER: width at byte 18, height at byte 22,
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/// both little-endian int32; height may be negative for top-down bitmaps). Used to give the VM the
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/// texture size that opcode 0x208 (get-texture-size) needs, without decoding pixels. Our textures are
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/// pre-converted BMPs (tools/convert_agf.py).
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/// </summary>
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public static class BmpHeader
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{
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public static (int Width, int Height) ReadDims(string? path)
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{
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if (string.IsNullOrEmpty(path) || !File.Exists(path)) return (0, 0);
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try
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{
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var b = new byte[26];
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using var fs = File.OpenRead(path);
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if (fs.Read(b, 0, 26) < 26 || b[0] != (byte)'B' || b[1] != (byte)'M') return (0, 0);
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int w = System.BitConverter.ToInt32(b, 18);
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int h = System.BitConverter.ToInt32(b, 22);
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return (System.Math.Abs(w), System.Math.Abs(h));
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}
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catch { return (0, 0); }
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}
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}
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