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Added support for bump mapping.

pull/3/head
Chris Laurel 2001-02-28 01:55:07 +00:00
parent 1cf7e96de1
commit b0bf0f1377
2 changed files with 173 additions and 4 deletions
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172
src/texture.cpp
View File

@ -9,12 +9,16 @@
#define JPEG_SUPPORT
#include <cmath>
#include <fstream>
#include "gl.h"
#include "glext.h"
#ifdef JPEG_SUPPORT
#include "ijl.h"
#endif
#include "celestia.h"
#include "vecmath.h"
#include "texture.h"
using namespace std;
@ -88,10 +92,12 @@ CTexture::~CTexture()
delete[] pixels;
if (cmap != NULL)
delete[] cmap;
if (glName != 0)
glDeleteTextures(1, &glName);
}
void CTexture::bindName()
void CTexture::bindName(bool wrap)
{
if (pixels == NULL)
return;
@ -100,8 +106,8 @@ void CTexture::bindName()
glGenTextures(1, &tn);
glBindTexture(GL_TEXTURE_2D, tn);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrap ? GL_REPEAT : GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrap ? GL_REPEAT : GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
gluBuild2DMipmaps(GL_TEXTURE_2D,
@ -123,6 +129,85 @@ unsigned int CTexture::getName()
}
// Convert the texture to a normal map
void CTexture::normalMap(float scale, bool wrap)
{
// Make sure that we get the texture after it's been loaded with
// data, but before bindName was called and texel data deleted.
if (pixels == NULL)
{
DPRINTF("Texture::normalMap: no texel data!\n");
return;
}
unsigned char* npixels = new unsigned char[width * height * 4];
// Compute normals using differences between adjacent texels. Only
// the value of the first channel is considered with computing
// differences--this produces the expected results with greyscale
// textures.
for (int i = 0; i < height; i++)
{
for (int j = 0; j < width; j++)
{
int i0 = i;
int j0 = j;
int i1 = i - 1;
int j1 = j - 1;
if (i1 < 0)
{
if (wrap)
{
i1 = height - 1;
}
else
{
i0++;
i1++;
}
}
if (j1 < 0)
{
if (wrap)
{
j1 = width - 1;
}
else
{
j0++;
j1++;
}
}
int h00 = (int) pixels[(i0 * width + j0) * components];
int h10 = (int) pixels[(i0 * width + j1) * components];
int h01 = (int) pixels[(i1 * width + j0) * components];
float dx = (float) (h00 - h10) * (1.0f / 255.0f) * scale;
float dy = (float) (h00 - h01) * (1.0f / 255.0f) * scale;
float mag = (float) sqrt(dx * dx + dy * dy + 1.0f);
float rmag = 1.0f / mag;
int n = (i * width + j) * 4;
// npixels[n] = (unsigned char) (128 + 127 * dy * rmag);
// npixels[n + 1] = (unsigned char) (128 - 127 * dx * rmag);
npixels[n] = (unsigned char) (128 - 127 * dx * rmag);
npixels[n + 1] = (unsigned char) (128 + 127 * dy * rmag);
npixels[n + 2] = (unsigned char) (128 + 127 * rmag);
npixels[n + 3] = 255;
}
}
delete[] pixels;
pixels = npixels;
format = GL_RGBA;
components = 4;
isNormalMap = true;
}
CTexture* CreateProceduralTexture(int width, int height,
int format,
ProceduralTexEval func)
@ -440,3 +525,84 @@ CTexture* CreateBMPTexture(const char* filename)
}
}
// Helper function for CreateNormalizationCubeMap
static Vec3f cubeVector(int face, float s, float t)
{
Vec3f v;
switch (face)
{
case 0:
v = Vec3f(1.0f, -t, -s);
break;
case 1:
v = Vec3f(-1.0f, -t, s);
break;
case 2:
v = Vec3f(s, 1.0f, t);
break;
case 3:
v = Vec3f(s, -1.0f, -t);
break;
case 4:
v = Vec3f(s, -t, 1.0f);
break;
case 5:
v = Vec3f(-s, -t, -1.0f);
break;
default:
// assert(false);
break;
}
v.normalize();
return v;
}
// Build a normalization cube map. This is used when bump mapping to keep
// the light vector unit length when interpolating. bindName() need not
// (and must not) be called for a texture created with this method, as the
// name binding stuff all handled right here.
CTexture* CreateNormalizationCubeMap(int size)
{
// assert(ExtensionSupported("GL_EXT_texture_cube_map"));
CTexture* tex = new CTexture(size, size, GL_RGB);
if (tex == NULL)
return NULL;
GLuint tn;
glGenTextures(1, &tn);
glBindTexture(GL_TEXTURE_2D, tn);
glTexParameteri(GL_TEXTURE_CUBE_MAP_EXT, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP_EXT, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP_EXT, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP_EXT, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
for (int face = 0; face < 6; face++)
{
for (int y = 0; y < size; y++)
{
for (int x = 0; x < size; x++)
{
float s = (float) x / (float) size * 2 - 1;
float t = (float) y / (float) size * 2 - 1;
Vec3f v = cubeVector(face, s, t);
tex->pixels[(y * size + x) * 3] = 128 + (int) (127 * v.x);
tex->pixels[(y * size + x) * 3 + 1] = 128 + (int) (127 * v.y);
tex->pixels[(y * size + x) * 3 + 2] = 128 + (int) (127 * v.z);
}
}
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X_EXT + face,
0, GL_RGB8,
size, size,
0, GL_RGB,
GL_UNSIGNED_BYTE,
tex->pixels);
}
return tex;
}

5
src/texture.h
View File

@ -22,8 +22,9 @@ class CTexture
CTexture(int w, int h, int fmt);
~CTexture();
void bindName();
void bindName(bool wrap = false);
unsigned int getName();
void normalMap(float scale, bool wrap);
enum {
ColorChannel = 1,
@ -35,6 +36,7 @@ class CTexture
int height;
int components;
int format;
bool isNormalMap;
unsigned char* pixels;
int cmapEntries;
@ -54,5 +56,6 @@ extern CTexture* CreateBMPTexture(const char* filename);
extern CTexture* LoadTextureFromFile(string filename);
extern CTexture* CreateNormalizationCubeMap(int size);
#endif // _TEXTURE_H_