265 lines
7.1 KiB
C++
Executable File
265 lines
7.1 KiB
C++
Executable File
//
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// KRViewport.cpp
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// KREngine
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//
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// Created by Kearwood Gilbert on 2012-10-25.
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// Copyright (c) 2012 Kearwood Software. All rights reserved.
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//
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#define KRENGINE_SWAP_INT(x,y) {int t;t=x;x=y;y=t;}
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#include "KREngine-common.h"
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#include "KRViewport.h"
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KRViewport::KRViewport()
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{
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m_size = KRVector2::One();
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m_matProjection = KRMat4();
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m_matView = KRMat4();
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m_lodBias = 0.0f;
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calculateDerivedValues();
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}
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KRViewport::KRViewport(const KRVector2 &size, const KRMat4 &matView, const KRMat4 &matProjection)
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{
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m_size = size;
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m_matView = matView;
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m_matProjection = matProjection;
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calculateDerivedValues();
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}
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KRViewport& KRViewport::operator=(const KRViewport &v) {
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if(this != &v) { // Prevent self-assignment.
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m_size = v.m_size;
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m_matProjection = v.m_matProjection;
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m_matView = v.m_matView;
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m_lodBias = v.m_lodBias;
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calculateDerivedValues();
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}
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return *this;
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}
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KRViewport::~KRViewport()
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{
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}
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const KRVector2 &KRViewport::getSize() const
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{
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return m_size;
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}
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const KRMat4 &KRViewport::getViewMatrix() const
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{
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return m_matView;
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}
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const KRMat4 &KRViewport::getProjectionMatrix() const
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{
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return m_matProjection;
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}
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void KRViewport::setSize(const KRVector2 &size)
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{
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m_size = size;
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}
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void KRViewport::setViewMatrix(const KRMat4 &matView)
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{
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m_matView = matView;
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calculateDerivedValues();
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}
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void KRViewport::setProjectionMatrix(const KRMat4 &matProjection)
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{
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m_matProjection = matProjection;
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calculateDerivedValues();
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}
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const KRMat4 &KRViewport::KRViewport::getViewProjectionMatrix() const
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{
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return m_matViewProjection;
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}
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const KRMat4 &KRViewport::getInverseViewMatrix() const
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{
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return m_matInverseView;
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}
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const KRMat4 &KRViewport::getInverseProjectionMatrix() const
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{
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return m_matInverseProjection;
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}
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const KRVector3 &KRViewport::getCameraDirection() const
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{
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return m_cameraDirection;
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}
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const KRVector3 &KRViewport::getCameraPosition() const
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{
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return m_cameraPosition;
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}
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const int *KRViewport::getFrontToBackOrder() const
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{
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return &m_frontToBackOrder[0];
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}
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const int *KRViewport::getBackToFrontOrder() const
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{
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return &m_backToFrontOrder[0];
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}
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void KRViewport::calculateDerivedValues()
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{
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m_matViewProjection = m_matView * m_matProjection;
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m_matInverseView = KRMat4::Invert(m_matView);
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m_matInverseProjection = KRMat4::Invert(m_matProjection);
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m_cameraPosition = KRMat4::Dot(m_matInverseView, KRVector3::Zero());
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m_cameraDirection = KRMat4::Dot(m_matInverseView, KRVector3(0.0, 0.0, 1.0)) - KRMat4::Dot(m_matInverseView, KRVector3(0.0, 0.0, 0.0));
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for(int i=0; i<8; i++) {
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m_frontToBackOrder[i] = i;
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}
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if(m_cameraDirection.x > 0.0) {
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KRENGINE_SWAP_INT(m_frontToBackOrder[0], m_frontToBackOrder[1]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[2], m_frontToBackOrder[3]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[4], m_frontToBackOrder[5]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[6], m_frontToBackOrder[7]);
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}
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if(m_cameraDirection.y > 0.0) {
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KRENGINE_SWAP_INT(m_frontToBackOrder[0], m_frontToBackOrder[2]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[1], m_frontToBackOrder[3]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[4], m_frontToBackOrder[6]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[5], m_frontToBackOrder[7]);
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}
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if(m_cameraDirection.z > 0.0) {
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KRENGINE_SWAP_INT(m_frontToBackOrder[0], m_frontToBackOrder[4]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[1], m_frontToBackOrder[5]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[2], m_frontToBackOrder[6]);
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KRENGINE_SWAP_INT(m_frontToBackOrder[3], m_frontToBackOrder[7]);
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}
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for(int i=0; i<8; i++) {
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m_backToFrontOrder[i] = m_frontToBackOrder[7-i];
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}
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}
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unordered_map<KRAABB, int> &KRViewport::getVisibleBounds()
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{
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return m_visibleBounds;
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}
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float KRViewport::getLODBias() const
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{
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return m_lodBias;
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}
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void KRViewport::setLODBias(float lod_bias)
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{
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m_lodBias = lod_bias;
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}
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float KRViewport::coverage(const KRAABB &b) const
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{
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if(!visible(b)) {
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return 0.0f; // Culled out by view frustrum
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} else {
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KRVector3 nearest_point = b.nearestPoint(getCameraPosition());
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float distance = (nearest_point - getCameraPosition()).magnitude();
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KRVector3 v = KRMat4::DotWDiv(m_matProjection, getCameraPosition() + getCameraDirection() * distance);
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float screen_depth = distance / 1000.0f;
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return KRCLAMP(1.0f - screen_depth, 0.01f, 1.0f);
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/*
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KRVector2 screen_min;
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KRVector2 screen_max;
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// Loop through all corners and transform them to screen space
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for(int i=0; i<8; i++) {
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KRVector3 screen_pos = KRMat4::DotWDiv(m_matViewProjection, KRVector3(i & 1 ? b.min.x : b.max.x, i & 2 ? b.min.y : b.max.y, i & 4 ? b.min.z : b.max.z));
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if(i==0) {
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screen_min = screen_pos.xy();
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screen_max = screen_pos.xy();
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} else {
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if(screen_pos.x < screen_min.x) screen_min.x = screen_pos.x;
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if(screen_pos.y < screen_min.y) screen_min.y = screen_pos.y;
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if(screen_pos.x > screen_max.x) screen_max.x = screen_pos.x;
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if(screen_pos.y > screen_max.y) screen_max.y = screen_pos.y;
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}
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}
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screen_min.x = KRCLAMP(screen_min.x, 0.0f, 1.0f);
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screen_min.y = KRCLAMP(screen_min.y, 0.0f, 1.0f);
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screen_max.x = KRCLAMP(screen_max.x, 0.0f, 1.0f);
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screen_max.y = KRCLAMP(screen_max.y, 0.0f, 1.0f);
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float c = (screen_max.x - screen_min.x) * (screen_max.y - screen_min.y);
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return KRCLAMP(c, 0.01f, 1.0f);
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*/
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}
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}
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bool KRViewport::visible(const KRAABB &b) const
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{
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// test if bounding box would be within the visible range of the clip space transformed by matViewProjection
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// This is used for view frustrum culling
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int outside_count[6] = {0, 0, 0, 0, 0, 0};
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for(int iCorner=0; iCorner<8; iCorner++) {
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KRVector4 sourceCornerVertex = KRVector4(
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(iCorner & 1) == 0 ? b.min.x : b.max.x,
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(iCorner & 2) == 0 ? b.min.y : b.max.y,
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(iCorner & 4) == 0 ? b.min.z : b.max.z, 1.0f);
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KRVector4 cornerVertex = KRMat4::Dot4(m_matViewProjection, sourceCornerVertex);
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if(cornerVertex.x < -cornerVertex.w) {
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outside_count[0]++;
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}
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if(cornerVertex.y < -cornerVertex.w) {
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outside_count[1]++;
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}
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if(cornerVertex.z < -cornerVertex.w) {
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outside_count[2]++;
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}
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if(cornerVertex.x > cornerVertex.w) {
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outside_count[3]++;
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}
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if(cornerVertex.y > cornerVertex.w) {
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outside_count[4]++;
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}
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if(cornerVertex.z > cornerVertex.w) {
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outside_count[5]++;
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}
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}
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bool is_visible = true;
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for(int iFace=0; iFace < 6; iFace++) {
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if(outside_count[iFace] == 8) {
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is_visible = false;
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}
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}
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return is_visible;
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}
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