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// all these must be powers of two |
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#define TC_WIDTH 256 |
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#define TC_HEIGHT 256 |
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#define TC_ROUND 4 |
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|
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typedef struct { |
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GLuint name; |
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int x, y, w, h; |
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} tc_area; |
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|
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void tc_get (tc_area *area, int width, int height); |
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void tc_put (tc_area *area); |
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void tc_clear (); |
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|
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///////////////////////////////////////////////////////////////////////////// |
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|
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#include <glib.h> |
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|
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typedef struct tc_texture { |
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struct tc_texture *next; |
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GLuint name; |
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int avail; |
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} tc_texture; |
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|
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typedef struct tc_slice { |
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GLuint name; |
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int avail, y; |
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} tc_slice; |
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|
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static tc_slice slices[TC_HEIGHT / TC_ROUND]; |
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static tc_texture *first_texture; |
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|
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void |
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tc_clear () |
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{ |
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int i; |
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|
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for (i = TC_HEIGHT / TC_ROUND; i--; ) |
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slices [i].name = 0; |
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|
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while (first_texture) |
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{ |
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tc_texture *next = first_texture->next; |
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glDeleteTextures (1, &first_texture->name); |
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g_slice_free (tc_texture, first_texture); |
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first_texture = next; |
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} |
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} |
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|
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void |
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tc_get (tc_area *area, int width, int height) |
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{ |
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int slice_height = MIN (height + TC_ROUND - 1, TC_HEIGHT) & ~(TC_ROUND - 1); |
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tc_slice *slice = slices + slice_height / TC_ROUND; |
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|
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area->w = width; |
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area->h = height; |
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|
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width = MIN (width, TC_WIDTH); |
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|
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if (!slice->name || slice->avail < width) |
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{ |
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// try to find a texture with enough space |
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tc_texture *tex, *match = 0; |
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|
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for (tex = first_texture; tex; tex = tex->next) |
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if (tex->avail >= slice_height && (!match || match->avail > tex->avail)) |
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match = tex; |
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|
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// create a new texture if necessary |
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if (!match) |
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{ |
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match = g_slice_new (tc_texture); |
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match->next = first_texture; |
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first_texture = match; |
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glGenTextures (1, &match->name); |
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match->avail = TC_HEIGHT; |
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|
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glBindTexture (GL_TEXTURE_2D, match->name); |
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); |
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); |
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glTexImage2D (GL_TEXTURE_2D, 0, GL_ALPHA, TC_WIDTH, TC_HEIGHT, 0, GL_ALPHA, GL_UNSIGNED_BYTE, 0); |
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} |
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|
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match->avail -= slice_height; |
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|
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slice->name = match->name; |
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slice->avail = TC_WIDTH; |
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slice->y = match->avail; |
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} |
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|
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slice->avail -= width; |
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|
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area->name = slice->name; |
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area->x = slice->avail; |
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area->y = slice->y; |
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} |
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|
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void |
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tc_put (tc_area *area) |
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{ |
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// our management is too primitive to support this operation yet |
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} |