mirror of
https://github.com/ZDoom/gzdoom.git
synced 2024-12-12 13:42:29 +00:00
118 lines
3.6 KiB
C++
118 lines
3.6 KiB
C++
/*
|
|
** SSA barycentric weight and viewport calculations
|
|
** Copyright (c) 2016 Magnus Norddahl
|
|
**
|
|
** This software is provided 'as-is', without any express or implied
|
|
** warranty. In no event will the authors be held liable for any damages
|
|
** arising from the use of this software.
|
|
**
|
|
** Permission is granted to anyone to use this software for any purpose,
|
|
** including commercial applications, and to alter it and redistribute it
|
|
** freely, subject to the following restrictions:
|
|
**
|
|
** 1. The origin of this software must not be misrepresented; you must not
|
|
** claim that you wrote the original software. If you use this software
|
|
** in a product, an acknowledgment in the product documentation would be
|
|
** appreciated but is not required.
|
|
** 2. Altered source versions must be plainly marked as such, and must not be
|
|
** misrepresented as being the original software.
|
|
** 3. This notice may not be removed or altered from any source distribution.
|
|
**
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include "ssa_vec4f.h"
|
|
#include "ssa_float.h"
|
|
#include "ssa_int.h"
|
|
|
|
class SSAViewport
|
|
{
|
|
public:
|
|
SSAViewport(SSAInt x, SSAInt y, SSAInt width, SSAInt height)
|
|
: x(x), y(y), width(width), height(height), right(x + width), bottom(y + height),
|
|
half_width(SSAFloat(width) * 0.5f), half_height(SSAFloat(height) * 0.5f),
|
|
rcp_half_width(1.0f / (SSAFloat(width) * 0.5f)),
|
|
rcp_half_height(1.0f / (SSAFloat(height) * 0.5f))
|
|
{
|
|
}
|
|
|
|
SSAInt x, y;
|
|
SSAInt width, height;
|
|
SSAInt right, bottom;
|
|
SSAFloat half_width;
|
|
SSAFloat half_height;
|
|
SSAFloat rcp_half_width;
|
|
SSAFloat rcp_half_height;
|
|
|
|
SSAVec4f clip_to_window(SSAVec4f clip) const
|
|
{
|
|
SSAFloat w = clip[3];
|
|
SSAVec4f normalized = SSAVec4f::insert_element(clip / SSAVec4f::shuffle(clip, 3, 3, 3, 3), w, 3);
|
|
return normalized_to_window(normalized);
|
|
}
|
|
|
|
SSAVec4f normalized_to_window(SSAVec4f normalized) const
|
|
{
|
|
return SSAVec4f(
|
|
SSAFloat(x) + (normalized[0] + 1.0f) * half_width,
|
|
SSAFloat(y) + (normalized[1] + 1.0f) * half_height,
|
|
0.0f - normalized[2],
|
|
normalized[3]);
|
|
}
|
|
};
|
|
|
|
class SSABarycentricWeight
|
|
{
|
|
public:
|
|
SSABarycentricWeight(SSAViewport vp, SSAVec4f v1, SSAVec4f v2);
|
|
SSAFloat from_window_x(SSAInt x) const;
|
|
SSAFloat from_window_y(SSAInt y) const;
|
|
|
|
SSAViewport viewport;
|
|
SSAVec4f v1;
|
|
SSAVec4f v2;
|
|
};
|
|
|
|
inline SSABarycentricWeight::SSABarycentricWeight(SSAViewport viewport, SSAVec4f v1, SSAVec4f v2)
|
|
: viewport(viewport), v1(v1), v2(v2)
|
|
{
|
|
}
|
|
|
|
inline SSAFloat SSABarycentricWeight::from_window_x(SSAInt x) const
|
|
{
|
|
/* SSAFloat xnormalized = (x + 0.5f - viewport.x) * viewport.rcp_half_width - 1.0f;
|
|
SSAFloat dx = v2.x-v1.x;
|
|
SSAFloat dw = v2.w-v1.w;
|
|
SSAFloat a = (v2.x - xnormalized * v2.w) / (dx - xnormalized * dw);
|
|
return a;*/
|
|
|
|
SSAFloat xnormalized = (SSAFloat(x) + 0.5f - SSAFloat(viewport.x)) * viewport.rcp_half_width - 1.0f;
|
|
SSAFloat dx = v2[0]-v1[0];
|
|
SSAFloat dw = v2[3]-v1[3];
|
|
SSAFloat t = (xnormalized * v1[3] - v1[0]) / (dx - xnormalized * dw);
|
|
return 1.0f - t;
|
|
}
|
|
|
|
inline SSAFloat SSABarycentricWeight::from_window_y(SSAInt y) const
|
|
{
|
|
/* SSAFloat ynormalized = (y + 0.5f - viewport.y) * viewport.rcp_half_height - 1.0f;
|
|
SSAFloat dy = v2.y-v1.y;
|
|
SSAFloat dw = v2.w-v1.w;
|
|
SSAFloat a = (v2.y - ynormalized * v2.w) / (dy - ynormalized * dw);
|
|
return a;*/
|
|
|
|
SSAFloat ynormalized = (SSAFloat(y) + 0.5f - SSAFloat(viewport.y)) * viewport.rcp_half_height - 1.0f;
|
|
SSAFloat dy = v2[1]-v1[1];
|
|
SSAFloat dw = v2[3]-v1[3];
|
|
SSAFloat t = (ynormalized * v1[3] - v1[1]) / (dy - ynormalized * dw);
|
|
return 1.0f - t;
|
|
}
|
|
|
|
/*
|
|
y = (v1.y + t * dy) / (v1.w + t * dw)
|
|
|
|
y * v1.w + y * t * dw = v1.y + t * dy
|
|
y * v1.w - v1.y = t * (dy - y * dw)
|
|
t = (y * v1.w - v1.y) / (dy - y * dw)
|
|
*/
|