145 lines
4.3 KiB
C++
145 lines
4.3 KiB
C++
#include "TerrainRayWalker.h"
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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):
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renderer(renderer)
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{
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}
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void TerrainRayWalker::update()
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{
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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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double disp = textures->getMaximalDisplacement();
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ymin = info.min_height - disp;
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ymax = info.max_height + disp;
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ydispmax = disp * (0.5 + (double)renderer->render_quality * 0.05);
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ydispmin = -ydispmax;
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minstep = 0.5 * terrain->scaling / (double)renderer->render_quality;
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maxstep = 50.0 * terrain->scaling / (double)renderer->render_quality;
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}
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static inline Vector3 _getShiftAxis(const Vector3 &direction)
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{
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if (fabs(direction.y) > 0.99)
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{
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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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}
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else
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{
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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, double max_length, TerrainHitResult &result)
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{
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TerrainRenderer* terrain_renderer = renderer->getTerrainRenderer();
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TexturesRenderer* textures_renderer = renderer->getTexturesRenderer();
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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 = minstep;
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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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{
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// Prepare escape
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if (renderer->render_quality >= 7)
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{
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shift_step = escape_angle / (double)(renderer->render_quality * renderer->render_quality);
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}
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else
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{
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shift_step = escape_angle / (double)renderer->render_quality;
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}
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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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{
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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, false);
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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 < ydispmin)
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{
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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 < ydispmax)
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{
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displaced = textures_renderer->displaceTerrain(terrain_result);
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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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{
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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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{
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result.escape_angle += shift_step;
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if (result.escape_angle > escape_angle)
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{
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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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}
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else
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{
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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 * 10.0 / (double)renderer->render_quality;
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if (step_length < minstep)
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{
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step_length = minstep;
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}
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else if (step_length > maxstep)
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{
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step_length = maxstep;
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}
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}
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} while (not hit and cursor.y < ymax and walked_length < max_length);
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return hit or result.escape_angle > 0.0;
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}
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