131 lines
4.7 KiB
C++
131 lines
4.7 KiB
C++
#include "TerrainRayWalker.h"
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#include <cmath>
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#include "SoftwareRenderer.h"
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#include "Scenery.h"
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#include "TerrainDefinition.h"
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#include "TexturesDefinition.h"
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#include "TerrainRenderer.h"
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#include "TexturesRenderer.h"
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#include "Matrix4.h"
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TerrainRayWalker::TerrainRayWalker(SoftwareRenderer *renderer) : renderer(renderer) {
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setQuality(0.5);
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}
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void TerrainRayWalker::setQuality(double displacement_safety, double minimal_step, double maximal_step,
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double step_factor, double max_distance, double escape_step) {
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this->displacement_safety = displacement_safety;
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this->minimal_step = minimal_step;
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this->maximal_step = maximal_step;
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this->step_factor = step_factor;
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this->max_distance = max_distance;
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this->escape_step = escape_step;
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}
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void TerrainRayWalker::setQuality(double factor) {
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setQuality(0.2 + 0.8 * factor, 1.0 / (factor * factor * 30.0 + 1.0), 50.0 / (factor * 10.0 + 1.0),
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1.0 / (factor * 10.0 + 1.0), 10.0 + factor * 200.0, factor * factor * 100.0);
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}
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void TerrainRayWalker::update() {
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TerrainDefinition *terrain = renderer->getScenery()->getTerrain();
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HeightInfo info = terrain->getHeightInfo();
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TexturesDefinition *textures = renderer->getScenery()->getTextures();
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displacement_base = textures->getMaximalDisplacement();
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ymin = info.min_height - displacement_base;
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ymax = info.max_height + displacement_base;
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}
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static inline Vector3 _getShiftAxis(const Vector3 &direction) {
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if (fabs(direction.y) > 0.99) {
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// When the ray is vertical, we choose an arbitrary shift axis
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return VECTOR_NORTH;
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} else {
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return VECTOR_UP.crossProduct(direction);
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}
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}
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bool TerrainRayWalker::startWalking(const Vector3 &start, Vector3 direction, double escape_angle,
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TerrainHitResult &result) {
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auto terrain_renderer = renderer->getTerrainRenderer();
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auto textures_renderer = renderer->getTexturesRenderer();
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auto textures_definition = renderer->getScenery()->getTextures();
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TerrainRenderer::TerrainResult terrain_result;
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Vector3 cursor, displaced;
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double diff;
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Matrix4 shift_matrix;
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double shift_step = 0.0;
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Vector3 previous_cursor = start;
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bool hit = false;
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double step_length = minimal_step;
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double walked_length = 0.0;
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result.escape_angle = 0.0;
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if (escape_angle != 0.0) {
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// Prepare escape
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shift_step = escape_angle / escape_step;
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shift_matrix = Matrix4::newRotateAxis(-shift_step, _getShiftAxis(direction));
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}
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do {
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// Perform a step
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cursor = previous_cursor.add(direction.scale(step_length));
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// Get the terrain info at end (without textures displacement)
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terrain_result = terrain_renderer->getResult(cursor.x, cursor.z, true);
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diff = cursor.y - terrain_result.location.y;
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// If we are very under the terrain, consider a hit
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if (diff < -displacement_base * displacement_safety) {
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hit = true;
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}
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// If we are close enough to the terrain, apply displacement
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else if (diff < displacement_base * displacement_safety) {
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displaced =
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textures_renderer->displaceTerrain(textures_definition, terrain_result.location, terrain_result.normal);
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diff = cursor.y - displaced.y;
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hit = diff < 0.0;
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}
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if (hit) {
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// TODO Refine the hit with dichotomy at high quality
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/*if (renderer->render_quality > 7)
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{
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cursor = refineHit(previous_cursor, cursor, step_length);
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}*/
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// Shift ray to escape terrain
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if (escape_angle != 0.0) {
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result.escape_angle += shift_step;
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if (result.escape_angle > escape_angle) {
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// Too much shifted to escape, make it a hit
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result.escape_angle = 0.0;
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return true;
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}
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hit = false;
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direction = shift_matrix.multPoint(direction);
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previous_cursor = start.add(shift_matrix.multPoint(previous_cursor.sub(start)));
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}
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result.hit_location = cursor;
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} else {
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// Prepare next step
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previous_cursor = cursor;
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walked_length += step_length;
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step_length = diff * step_factor;
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if (step_length < minimal_step) {
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step_length = minimal_step;
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} else if (step_length > maximal_step) {
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step_length = maximal_step;
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}
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}
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} while (not hit and cursor.y < ymax and walked_length < max_distance);
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return hit or result.escape_angle > 0.0;
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}
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