/**
* Prepare drawing a GL_ALPHA texture with the specified color.
*/
static void
PrepareColoredAlphaTexture(Color color)
{
#ifdef USE_GLSL
OpenGL::alpha_shader->Use();
color.Bind();
#else
color.Bind();
if (color == COLOR_BLACK) {
/* GL_ALPHA textures have black RGB - this is easy */
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
} else {
/* use GL_COMBINE to replace the texture color (black) with the
specified one */
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
/* replace the texture color with the selected text color */
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_REPLACE);
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_RGB, GL_PREVIOUS);
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
/* use the texture alpha */
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_REPLACE);
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_TEXTURE);
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
}
#endif
}
void
Canvas::DrawFilledRectangle(int left, int top, int right, int bottom,
const Color color)
{
#ifdef USE_GLSL
OpenGL::solid_shader->Use();
#endif
color.Bind();
std::unique_ptr<const GLBlend> blend;
if(!color.IsOpaque()) {
blend = std::make_unique<const GLBlend>(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
}
#ifdef HAVE_GLES
const RasterPoint vertices[] = {
{ left, top },
{ right, top },
{ left, bottom },
{ right, bottom },
};
const ScopeVertexPointer vp(vertices);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
#else
glRecti(left, top, right, bottom);
#endif
}
void DrawOutlineRectangle(int left, int top, int right, int bottom,
Color color) {
color.Bind();
#if defined(HAVE_GLES) && !defined(HAVE_GLES2)
glLineWidthx(1 << 16);
#else
glLineWidth(1);
#endif
OutlineRectangleGL(left, top, right, bottom);
}
void
Canvas::DrawHLine(int x1, int x2, int y, Color color)
{
color.Bind();
const RasterPoint v[] = {
{ GLvalue(x1), GLvalue(y) },
{ GLvalue(x2), GLvalue(y) },
};
const ScopeVertexPointer vp(v);
glDrawArrays(GL_LINE_STRIP, 0, ARRAY_SIZE(v));
}
void DrawOutlineRectangle(int left, int top, int right, int bottom,
Color color) {
color.Bind();
const unsigned scaledWidth=Layout::PenWidthPixels(1);
const unsigned glWidth=scaledWidth > OpenGL::max_linewidth ? OpenGL::max_linewidth : scaledWidth; // GL behavior seems to be undefined otherwise
#if defined(HAVE_GLES) && !defined(HAVE_GLES2)
glLineWidthx(glWidth << 16);
#else
glLineWidth(glWidth);
#endif
OutlineRectangleGL(left, top, right, bottom);
}
void
Canvas::StretchMono(int dest_x, int dest_y,
unsigned dest_width, unsigned dest_height,
const Bitmap &src,
int src_x, int src_y,
unsigned src_width, unsigned src_height,
Color fg_color, Color bg_color)
{
/* note that this implementation ignores the background color; it is
not mandatory, and we can assume that the background is already
set; it is only being passed to this function because the GDI
implementation will be faster when erasing the background
again */
#ifdef USE_GLSL
OpenGL::alpha_shader->Use();
fg_color.Bind();
#else
const GLEnable<GL_TEXTURE_2D> scope;
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
/* replace the texture color with the selected text color */
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_REPLACE);
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_RGB, GL_PREVIOUS);
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
/* invert texture alpha (our bitmaps have black text on white
background) */
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_REPLACE);
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_TEXTURE);
OpenGL::glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
#endif
const GLBlend blend(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
GLTexture &texture = *src.GetNative();
texture.Bind();
texture.Draw(dest_x, dest_y, dest_width, dest_height,
src_x, src_y, src_width, src_height);
}
/**
* Configures this brush in the OpenGL context.
*/
void Bind() const {
color.Bind();
}
/**
* Configure the Pen in the OpenGL context. Don't forget to call
* Unbind() when you're done with this Pen.
*/
void Bind() const {
color.Bind();
BindStyle();
}