1 #include <string.h>

2 #include <math.h>

3 #include "opengl.h"

4 #include "image.h"

5

6 static unsigned int next_pow2(unsigned int x);

7

8 Image::Image()

9 {

10 width = height = 0;

11 tex_width = tex_height = 0;

12 pixels = 0;

13 texture = 0;

14 own_pixels = 0;

15 }

16

17 Image::~Image()

18 {

19 destroy();

20 }

21

22 void Image::create(int xsz, int ysz, unsigned char *pix)

23 {

24 destroy();

25

26 pixels = own_pixels = new unsigned char[xsz * ysz * 3];

27 if(pix) {

28 memcpy(pixels, pix, xsz * ysz * 3);

29 } else {

30 memset(pixels, 0, xsz * ysz * 3);

31 }

32 width = xsz;

33 height = ysz;

34 }

35

36 void Image::destroy()

37 {

38 if(texture) {

39 glDeleteTextures(1, &texture);

40 texture = 0;

41 }

42

43 delete [] own_pixels;

44 own_pixels = pixels = 0;

45

46 width = height = tex_width = tex_height = 0;

47 }

48

49 unsigned int Image::gen_texture()

50 {

51 if(!pixels || !width || !height) {

52 return 0;

53 }

54

55 if(!texture) {

56 glGenTextures(1, &texture);

57 glBindTexture(GL_TEXTURE_2D, texture);

58 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);

59 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

60 glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);

61 } else {

62 glBindTexture(GL_TEXTURE_2D, texture);

63 }

64

65 tex_width = next_pow2(width);

66 tex_height = next_pow2(height);

67

68 if(tex_width == width && tex_height == height) {

69 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, tex_width, tex_height, 0,

70 GL_RGB, GL_UNSIGNED_BYTE, pixels);

71 } else {

72 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, tex_width, tex_height, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);

73 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height,

74 GL_RGB, GL_UNSIGNED_BYTE, pixels);

75 }

76

77 return texture;

78 }

79

80 static unsigned int next_pow2(unsigned int x)

81 {

82 --x;

83 x |= x >> 1;

84 x |= x >> 2;

85 x |= x >> 4;

86 x |= x >> 8;

87 x |= x >> 16;

88 return x + 1;

89 }