124 lines
4.8 KiB
C
124 lines
4.8 KiB
C
////////////////////////////////////////////////////////////
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//~ Shape helpers
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void V_DrawPoly(Arena *verts_arena, Arena *idxs_arena, Vec2Array points, Vec4 color_lin, V_DrawFlag flags)
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{
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if (flags & V_DrawFlag_Line)
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{
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i32 verts_count = points.count;
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if (verts_count >= 2)
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{
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TempArena scratch = BeginScratchNoConflict();
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{
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f32 half_thickness = 1;
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i32 lines_count = verts_count == 2 ? 1 : verts_count;
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i32 line_verts_count = lines_count * 4;
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i32 idx_count = lines_count * 6;
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i32 idx_offset = ArenaCount(verts_arena, V_DVert);
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/* Push dverts */
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V_DVert *dverts = PushStructsNoZero(verts_arena, V_DVert, line_verts_count);
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for (i32 line_idx = 0; line_idx < lines_count; ++line_idx)
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{
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i32 a_idx = line_idx;
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i32 b_idx = line_idx + 1;
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if (b_idx >= lines_count)
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{
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b_idx = 0;
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}
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Vec2 a = points.points[a_idx];
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Vec2 b = points.points[b_idx];
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Vec2 a_to_b = SubVec2(b, a);
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Vec2 perp = Vec2WithLen(PerpVec2(a_to_b), half_thickness);
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Vec2 p0 = AddVec2(a, perp);
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Vec2 p1 = SubVec2(a, perp);
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Vec2 p2 = SubVec2(b, perp);
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Vec2 p3 = AddVec2(b, perp);
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i32 offset = line_idx * 4;
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dverts[offset + 0] = (V_DVert) { .pos = p0, .color_lin = color_lin };
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dverts[offset + 1] = (V_DVert) { .pos = p1, .color_lin = color_lin };
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dverts[offset + 2] = (V_DVert) { .pos = p2, .color_lin = color_lin };
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dverts[offset + 3] = (V_DVert) { .pos = p3, .color_lin = color_lin };
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}
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/* Generate indices */
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i32 *indices = PushStructsNoZero(idxs_arena, i32, idx_count);
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for (i32 line_idx = 0; line_idx < lines_count; ++line_idx)
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{
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i32 indices_offset = line_idx * 6;
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i32 vert_idx_offset = idx_offset + (line_idx * 4);
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indices[indices_offset + 0] = vert_idx_offset + 0;
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indices[indices_offset + 1] = vert_idx_offset + 1;
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indices[indices_offset + 2] = vert_idx_offset + 2;
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indices[indices_offset + 3] = vert_idx_offset + 0;
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indices[indices_offset + 4] = vert_idx_offset + 2;
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indices[indices_offset + 5] = vert_idx_offset + 3;
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}
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}
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EndScratch(scratch);
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}
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}
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else
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{
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i32 verts_count = points.count;
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if (verts_count >= 3)
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{
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i32 idx_offset = ArenaCount(verts_arena, V_DVert);
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i32 tris_count = verts_count - 2;
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i32 idx_count = tris_count * 3;
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/* Push dverts */
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V_DVert *dverts = PushStructsNoZero(verts_arena, V_DVert, verts_count);
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for (i32 point_idx = 0; point_idx < (i32)points.count; ++point_idx)
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{
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V_DVert *dvert = &dverts[point_idx];
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dvert->pos = points.points[point_idx];
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dvert->color_lin = color_lin;
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}
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/* Generate indices in a fan pattern */
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i32 *indices = PushStructsNoZero(idxs_arena, i32, idx_count);
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for (i32 i = 0; i < tris_count; ++i)
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{
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i32 tri_offset = i * 3;
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indices[tri_offset + 0] = idx_offset;
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indices[tri_offset + 1] = idx_offset + i + 1;
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indices[tri_offset + 2] = idx_offset + i + 2;
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}
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}
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}
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}
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void V_DrawShape(Arena *verts_arena, Arena *idxs_arena, S_Shape shape, Vec4 color_lin, i32 detail, V_DrawFlag flags)
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{
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if (shape.radius == 0)
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{
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Vec2Array draw_points = Zi;
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draw_points.points = shape.points;
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draw_points.count = shape.points_count;
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V_DrawPoly(verts_arena, idxs_arena, draw_points, color_lin, flags);
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}
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else
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{
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TempArena scratch = BeginScratchNoConflict();
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{
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Vec2Array draw_points = Zi;
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draw_points.points = PushStructsNoZero(scratch.arena, Vec2, detail);
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draw_points.count = detail;
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for (i32 i = 0; i < detail; ++i)
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{
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f32 rad = ((f32)i / (f32)detail) * Tau;
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Vec2 dir = Vec2FromAngle(rad);
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Vec2 sp = S_SupportPointFromShape(shape, dir);
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draw_points.points[i] = sp;
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}
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V_DrawPoly(verts_arena, idxs_arena, draw_points, color_lin, flags);
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}
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EndScratch(scratch);
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}
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}
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