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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include "common/scummsys.h"
#if defined(USE_OPENGL)
#include "backends/graphics/opengl/gltexture.h"
#include "backends/graphics/opengl/glerrorcheck.h"
#include "common/rect.h"
#include "common/array.h"
#include "common/util.h"
#include "common/tokenizer.h"
// Supported GL extensions
static bool npot_supported = false;
static bool glext_inited = false;
/*static inline GLint xdiv(int numerator, int denominator) {
assert(numerator < (1 << 16));
return (numerator << 16) / denominator;
}*/
static GLuint nextHigher2(GLuint v) {
if (v == 0)
return 1;
v--;
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
return ++v;
}
void GLTexture::initGLExtensions() {
// Return if extensions were already checked
if (glext_inited)
return;
// Get a string with all extensions
const char* ext_string =
reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS));
CHECK_GL_ERROR();
Common::StringTokenizer tokenizer(ext_string, " ");
// Iterate all string tokens
while (!tokenizer.empty()) {
Common::String token = tokenizer.nextToken();
if (token == "GL_ARB_texture_non_power_of_two")
npot_supported = true;
}
glext_inited = true;
}
GLTexture::GLTexture(byte bpp, GLenum internalFormat, GLenum format, GLenum type)
:
_bytesPerPixel(bpp),
_internalFormat(internalFormat),
_glFormat(format),
_glType(type),
_textureWidth(0),
_textureHeight(0),
_realWidth(0),
_realHeight(0),
_refresh(false),
_filter(GL_NEAREST) {
// Generate the texture ID
glGenTextures(1, &_textureName); CHECK_GL_ERROR();
}
GLTexture::~GLTexture() {
// Delete the texture
glDeleteTextures(1, &_textureName); CHECK_GL_ERROR();
}
void GLTexture::refresh() {
// Delete previous texture
glDeleteTextures(1, &_textureName); CHECK_GL_ERROR();
// Generate the texture ID
glGenTextures(1, &_textureName); CHECK_GL_ERROR();
_refresh = true;
}
void GLTexture::allocBuffer(GLuint w, GLuint h) {
_realWidth = w;
_realHeight = h;
if (w <= _textureWidth && h <= _textureHeight && !_refresh)
// Already allocated a sufficiently large buffer
return;
if (npot_supported) {
_textureWidth = w;
_textureHeight = h;
} else {
_textureWidth = nextHigher2(w);
_textureHeight = nextHigher2(h);
}
// Select this OpenGL texture
glBindTexture(GL_TEXTURE_2D, _textureName); CHECK_GL_ERROR();
// Set the texture parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, _filter); CHECK_GL_ERROR();
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, _filter); CHECK_GL_ERROR();
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); CHECK_GL_ERROR();
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); CHECK_GL_ERROR();
// Allocate room for the texture
glTexImage2D(GL_TEXTURE_2D, 0, _internalFormat,
_textureWidth, _textureHeight, 0, _glFormat, _glType, NULL); CHECK_GL_ERROR();
_refresh = false;
}
void GLTexture::updateBuffer(const void *buf, int pitch, GLuint x, GLuint y, GLuint w, GLuint h) {
// Skip empty updates.
if (w * h == 0)
return;
// Select this OpenGL texture
glBindTexture(GL_TEXTURE_2D, _textureName); CHECK_GL_ERROR();
// Check if the buffer has its data contiguously
if (static_cast<int>(w) * _bytesPerPixel == pitch) {
glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, w, h,
_glFormat, _glType, buf); CHECK_GL_ERROR();
} else {
// Update the texture row by row
const byte *src = static_cast<const byte *>(buf);
do {
glTexSubImage2D(GL_TEXTURE_2D, 0, x, y,
w, 1, _glFormat, _glType, src); CHECK_GL_ERROR();
++y;
src += pitch;
} while (--h);
}
}
void GLTexture::drawTexture(GLshort x, GLshort y, GLshort w, GLshort h) {
// Select this OpenGL texture
glBindTexture(GL_TEXTURE_2D, _textureName); CHECK_GL_ERROR();
// Calculate the texture rect that will be drawn
const GLfloat texWidth = (GLfloat)_realWidth / _textureWidth;//xdiv(_surface.w, _textureWidth);
const GLfloat texHeight = (GLfloat)_realHeight / _textureHeight;//xdiv(_surface.h, _textureHeight);
const GLfloat texcoords[] = {
0, 0,
texWidth, 0,
0, texHeight,
texWidth, texHeight,
};
glTexCoordPointer(2, GL_FLOAT, 0, texcoords); CHECK_GL_ERROR();
// Calculate the screen rect where the texture will be drawn
const GLshort vertices[] = {
x, y,
x + w, y,
x, y + h,
x + w, y + h,
};
glVertexPointer(2, GL_SHORT, 0, vertices); CHECK_GL_ERROR();
// Draw the texture to the screen buffer
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); CHECK_GL_ERROR();
}
#endif
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