Uint8 Image::GetAlpha() {
Uint8 ret = 0;
if (SDL_GetTextureAlphaMod(texture, &ret)) {
std::ostringstream msg;
msg << "Failed to get alpha; " << SDL_GetError();
throw(std::runtime_error(msg.str()));
}
return ret;
}
/*
--------------------------------------------------------------------------------
GET ALPHA
--------------------------------------------------------------------------------
* Get the alpha value from the texture and return it
*/
Uint8 Texture::get_alpha( void )
{
Uint8 alpha;
SDL_GetTextureAlphaMod( mTexture, &alpha );
return( alpha );
}
/**
* @brief Test to see if we can vary the alpha of the texture. Helper function.
*
* \sa
* http://wiki.libsdl.org/moin.cgi/SDL_SetTextureAlphaMod
* http://wiki.libsdl.org/moin.cgi/SDL_GetTextureAlphaMod
* http://wiki.libsdl.org/moin.cgi/SDL_DestroyTexture
*/
static int
_hasTexAlpha(void)
{
int fail;
int ret;
SDL_Texture *tface;
Uint8 a;
/* Get test face. */
tface = _loadTestFace();
if (tface == NULL)
return 0;
/* See if supported. */
fail = 0;
ret = SDL_SetTextureAlphaMod( tface, 100 );
if (!_isSupported(ret))
fail = 1;
ret = SDL_GetTextureAlphaMod( tface, &a );
if (!_isSupported(ret))
fail = 1;
/* Clean up. */
SDL_DestroyTexture( tface );
if (fail)
return 0;
else if (a != 100)
return 0;
return 1;
}
/*
--------------------------------------------------------------------------------
RENDER FADE
--------------------------------------------------------------------------------
* This method is similar to render_self() except it also gets and modifies the
* alpha value of the texture instance, in effect, 'fading it out'.
*/
void Texture::render_fade( void )
{
if( mFading )
{
/* Get the alpha value */
Uint8 a;
SDL_GetTextureAlphaMod( mTexture, &a );
/* Decrease the alpha value or set it to zero */
if( a >= 8 )
a -= 8;
else
a = 0;
/* Apply the modified alpha to the texture */
SDL_SetTextureAlphaMod( mTexture, a );
/* Create the draw rect and render the texture */
SDL_Rect dRect = { mPos.x, mPos.y, mWidth, mHeight };
SDL_RenderCopy( gRenderer, mTexture, NULL, &dRect );
/* If we've hit zero alpha, reset the texture and switch off fading */
if( a == 0 )
{
mFading = false;
SDL_SetTextureAlphaMod( mTexture, (Uint8)255 );
}
}
}
float image_get_alpha( void *image )
{
Uint8 alpha;
SDL_GetTextureAlphaMod( asset_image_handle(image), &alpha );
return ( alpha / 255.0f );
}
int Texture::GetAlphaMod()
{
Uint8 alpha;
if(SDL_GetTextureAlphaMod(m_texture, &alpha) == -1)
LOG_ERROR("Couldn't get alpha mod");
return alpha;
}
double Sprite::getAlpha(){
Uint8 alpha = 0;
const int rc = SDL_GetTextureAlphaMod(this->sdlTexture, &alpha);
if(rc != 0){
Log(ERROR) << "Could not get alpha value from Sprite (" << this->path << "). " << SDL_GetError();
}
return ((double)alpha); // /255.0
}
double Sprite::Alpha() {
Uint8 alpha = 0;
const int rc = SDL_GetTextureAlphaMod(m_sdl_texture, &alpha);
if(rc != 0) {
log_error() << "Could not get alpha value from Sprite (" << m_path << "). " <<
SDL_GetError();
}
return static_cast<double>(alpha);
}
CAMLprim value
caml_SDL_GetTextureAlphaMod(value texture)
{
Uint8 alpha;
int r =
SDL_GetTextureAlphaMod(
SDL_Texture_val(texture),
&alpha);
if (r)
caml_failwith("Sdltexture.get_alpha_mod");
return Val_uint8(alpha);
}
void Sprite::initTextureData()
{
if(m_pTexture)
{
// Get texture width and height
SDL_QueryTexture(m_pTexture, NULL, NULL, &m_width, &m_height);
// Get color mod
SDL_GetTextureColorMod(m_pTexture, &m_color.r, &m_color.g, &m_color.b);
// Get alpha
SDL_GetTextureAlphaMod(m_pTexture, &m_color.a);
}
}
void SpaceScene::render_cursor()
{
SDL_Point loc;
SDL_GetMouseState(&(loc.x), &(loc.y));
window->draw_absolute(cursor, loc);
if (cursor_frames > 90) {
Uint8 alpha;
SDL_GetTextureAlphaMod(cursor->getTexture(), &alpha);
if (alpha > 0) {
SDL_SetTextureAlphaMod(cursor->getTexture(), alpha-2);
}
}
}
int gytexture_alpha(GyTexture * self, uint8_t *a) {
return SDL_GetTextureAlphaMod(GY_TEXTURE_UNWRAP(self), a);
}
int Texture_GetAlpha(Texture* texture)
{
Uint8 currentAlpha;
int result = SDL_GetTextureAlphaMod(texture->texture, ¤tAlpha);
return (result == 0 ? currentAlpha : -1);
}
