129 lines
3.3 KiB
C++
129 lines
3.3 KiB
C++
#include "HeightMap.h"
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#include "stb_image.h"
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#include "vector.h"
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#include <GL/freeglut.h>
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#include <iostream>
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#include <string>
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HeightMap::HeightMap(const std::string &file)
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{
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int bpp;
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unsigned char* imgData = stbi_load(file.c_str(), &width, &height, &bpp, 4);
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auto heightAt = [&](int x, int y)
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{
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return (imgData[(x + y * width) * 4] / 256.0f) * 100.0f;
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};
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for (int y = 0; y < height-1; y++)
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{
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for (int x = 0; x < width-1; x++)
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{
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int offsets[4][2] = { { 0, 0 },{ 1, 0 },{ 1, 1 },{ 0, 1 } };
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Vec3f ca(0, heightAt(x, y + 1) - heightAt(x, y), 1);
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Vec3f ba(1, heightAt(x + 1, y) - heightAt(x, y), 0);
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Vec3f normal = ca.cross(ba);
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normal.Normalize();
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for (int i = 0; i < 4; i++)
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{
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float h = heightAt(x + offsets[i][0], y + offsets[i][1]);
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vertices.push_back(Vertex{ (float)(x + offsets[i][0])*scale, h*scale, (float)(y + offsets[i][1])*scale,
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normal.x, normal.y, normal.z,
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(x + offsets[i][0]) / (float)height, (y + offsets[i][1]) / (float)width } );
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}
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}
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}
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glGenTextures(1, &imageIndex);
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glBindTexture(GL_TEXTURE_2D, imageIndex);
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glTexImage2D(GL_TEXTURE_2D,
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0, //level
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GL_RGBA, //internal format
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width, //width
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height, //height
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0, //border
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GL_RGBA, //data format
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GL_UNSIGNED_BYTE, //data type
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imgData); //data
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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stbi_image_free(imgData);
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}
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HeightMap::~HeightMap()
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{
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glDeleteTextures(1, &imageIndex);
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}
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void HeightMap::Draw()
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{
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glEnable(GL_LIGHTING);
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float color[] = { 0.7f, 0.7f, 0.7f, 1 };
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glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, color);
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glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, color);
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glEnable(GL_TEXTURE_2D);
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glBindTexture(GL_TEXTURE_2D, imageIndex);
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//glDisable(GL_TEXTURE_2D);
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glEnableClientState(GL_VERTEX_ARRAY);
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glEnableClientState(GL_TEXTURE_COORD_ARRAY);
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//glEnableClientState(GL_COLOR_ARRAY);
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glEnableClientState(GL_NORMAL_ARRAY);
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glVertexPointer(3, GL_FLOAT, sizeof(Vertex), ((float*)vertices.data()) + 0);
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glTexCoordPointer(2, GL_FLOAT, sizeof(Vertex), ((float*)vertices.data()) + 6);
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glNormalPointer(GL_FLOAT, sizeof(Vertex), ((float*)vertices.data()) + 3);
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glDrawArrays(GL_QUADS, 0, vertices.size());
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glDisableClientState(GL_VERTEX_ARRAY);
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glDisableClientState(GL_TEXTURE_COORD_ARRAY);
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//glDisableClientState(GL_COLOR_ARRAY);
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glDisableClientState(GL_NORMAL_ARRAY);
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}
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void HeightMap::GetHeigth(float x, float y)
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{
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x /= scale;
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y /= scale;
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int ix = x;
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int iy = y;
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int index = (ix + (width - 1) * iy) * 4;
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Vertex& a = vertices[index];
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Vertex& b = vertices[index+1];
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Vertex& c = vertices[index+3];
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//http://stackoverflow.com/questions/36090269/finding-height-of-point-on-height-map-triangles
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}
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void HeightMap::SetTexture(const std::string &file)
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{
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int bpp, width2, height2;
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unsigned char* imgData = stbi_load(file.c_str(), &width2, &height2, &bpp, 4);
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glBindTexture(GL_TEXTURE_2D, imageIndex);
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glTexImage2D(GL_TEXTURE_2D,
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0, //level
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GL_RGBA, //internal format
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width2, //width
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height2, //height
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0, //border
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GL_RGBA, //data format
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GL_UNSIGNED_BYTE, //data type
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imgData); //data
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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stbi_image_free(imgData);
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} |