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twn_draw: proper ortho unproject

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veclavtalica 2025-03-08 04:38:56 +03:00
parent 78b6a26de9
commit 826622cd58
1 changed files with 18 additions and 6 deletions
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24
src/rendering/twn_draw.c
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@ -521,19 +521,31 @@ DrawCameraUnprojectResult draw_camera_unproject(Vec2 point,
.far_z = draw_distance
};
Matrix4 const projection_matrix = orthographic ? camera_orthographic(&camera) : camera_perspective(&camera);
Matrix4 const look_at_matrix = camera_look_at(&camera);
/* TODO: cache matrices for repeated camera inputs, those are expensive */
Matrix4 const inverse_view_proj = matrix_inverse(matrix_multiply(projection_matrix, look_at_matrix));
point.y = (float)ctx.base_render_height - point.y;
Vec4 v;
v.x = 2.0f * point.x / (float)ctx.base_render_width - 1.0f;
v.y = 2.0f * point.y / (float)ctx.base_render_height - 1.0f;
v.z = 2.0f * 1.0f - 1.0f;
v.z = 2.0f * 1.0f - 1.0f;
v.w = 1.0f;
/* simpler case, just shoot a point from viewbox face along the supplied direction */
if (orthographic) {
Vec3 right = vec3_cross(direction, up);
Vec3 aup = vec3_cross(direction, right);
return (DrawCameraUnprojectResult){
.direction = direction,
.position = vec3_add(vec3_add(position, vec3_scale(right, v.x * aspect/zoom)), vec3_scale(aup, -v.y * aspect/zoom)),
};
}
/* TODO: sanity check for point being in proper box? it would produce bogus results otherwise */
Matrix4 const projection_matrix = orthographic ? camera_orthographic(&camera) : camera_perspective(&camera);
Matrix4 const look_at_matrix = camera_look_at(&camera);
/* TODO: cache matrices for repeated camera inputs, those are expensive */
Matrix4 const inverse_view_proj = matrix_inverse(matrix_multiply(projection_matrix, look_at_matrix));
v = matrix_vector_multiply(inverse_view_proj, v);
/* TODO: is it even ever not equal to 1 in our case ? */