mirror of https://github.com/nmlgc/ReC98.git
79 lines
2.3 KiB
C++
79 lines
2.3 KiB
C++
#include <stddef.h>
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#include "platform.h"
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#include "x86real.h"
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#include "codegen.hpp"
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#include "pc98.h"
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#include "master.hpp"
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#include "th01/math/polar.hpp"
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#include "th01/math/subpixel.hpp"
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#include "th04/main/playfld.hpp"
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#pragma option -k-
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// Points that change from subpixel screen space to pixel screen space within
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// the same variable...
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union SpaceChangingPoint {
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SPPoint sp;
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screen_point_t pixel;
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};
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// Register parameters for vector2_at_opt().
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#define v_length_ _BX
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#define v_length static_cast<subpixel_t>(v_length_)
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#define v_angle _CX
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#define v_center_ _BP
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#define v_center reinterpret_cast<SPPoint __ss *>(v_center_)
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#define v_ret_ _DI
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#define v_ret reinterpret_cast<SpaceChangingPoint __ss *>(v_ret_)
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// Register parameters for build_line_in_pixels().
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#define p_0_ _DI
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#define p_0 reinterpret_cast<SpaceChangingPoint __ss *>(p_0_)
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#define p_1_ _BX
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#define p_1 reinterpret_cast<SpaceChangingPoint __ss *>(p_1_)
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#define p_distance_ _BP
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#define p_distance reinterpret_cast<SPPoint __ss *>(p_distance_)
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#define p_distance_offset 1
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// A regular vector2_at() function with [v_center], [v_angle], and [v_length].
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// Returns the Y coordinate of the resulting vector.
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subpixel_t near vector2_at_opt()
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{
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uint16_t table_offset = v_angle;
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table_offset += table_offset; // *= sizeof(short)
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_AX = polar_by_offset(v_center->x, v_length, CosTable8, table_offset);
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mov_to_mem(_SS, v_ret_, offsetof(point_t, x), _AX);
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_AX = polar_by_offset(v_center->y, v_length, SinTable8, table_offset);
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mov_to_mem(_SS, v_ret_, offsetof(point_t, y), _AX);
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return _AX;
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}
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// Calculates:
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// p_0 = p_0.to_pixel();
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// p_1 = (p_0 + p_distance).to_pixel();
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void near build_line_in_pixels()
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{
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#define tmp_0 _DX
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#define tmp_1 _AX
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tmp_1 = p_distance[p_distance_offset].x;
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mov_to_reg(tmp_0, _SS, p_0_, offsetof(SPPoint, x));
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tmp_1 += tmp_0;
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static_cast<pixel_t>(tmp_1) >>= SUBPIXEL_BITS;
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static_cast<pixel_t>(tmp_0) >>= SUBPIXEL_BITS;
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p_1->pixel.x = tmp_1;
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mov_to_mem(_SS, p_0_, offsetof(screen_point_t, x), tmp_0);
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tmp_1 = p_distance[p_distance_offset].y;
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mov_to_reg(tmp_0, _SS, p_0_, offsetof(SPPoint, y));
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tmp_1 += tmp_0;
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static_cast<pixel_t>(tmp_1) >>= SUBPIXEL_BITS;
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static_cast<pixel_t>(tmp_0) >>= SUBPIXEL_BITS;
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p_1->pixel.y = tmp_1;
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mov_to_mem(_SS, p_0_, offsetof(screen_point_t, y), tmp_0);
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#undef tmp_1
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#undef tmp_0
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}
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