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Cleanup and document GFX_StartUpdate function

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Usage of this function depends on the state of global sdl struct; and
it's very easy to make a mistake - documentation should lower this risk.

Change the type of output parameter 'pitch' and assure type safety with
internal SDL types via static asserts.
This commit is contained in:
Patryk Obara 2020-03-17 13:37:01 +01:00 • committed by Patryk Obara
parent 08934b2972
commit 0b173eec08
3 changed files with 35 additions and 24 deletions
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2
include/render.h
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@ -74,7 +74,7 @@ typedef struct {
ScalerLineHandler_t linePalHandler;
ScalerComplexHandler_t complexHandler;
Bitu blocks, lastBlock;
Bitu outPitch;
int outPitch;
Bit8u *outWrite;
Bitu cachePitch;
Bit8u *cacheRead;

2
include/video.h
View file

@ -64,7 +64,7 @@ void GFX_ResetScreen(void);
void GFX_Start(void);
void GFX_Stop(void);
void GFX_SwitchFullScreen(void);
bool GFX_StartUpdate(Bit8u * & pixels,Bitu & pitch);
bool GFX_StartUpdate(uint8_t * &pixels, int &pitch);
void GFX_EndUpdate( const Bit16u *changedLines );
void GFX_GetSize(int &width, int &height, bool &fullscreen);
void GFX_LosingFocus(void);

55
src/gui/sdlmain.cpp
View file

@ -257,8 +257,8 @@ struct SDL_Block {
#if C_OPENGL
struct {
SDL_GLContext context;
Bitu pitch;
void * framebuf; // TODO Use unique_ptr to prevent leak
int pitch = 0;
void *framebuf = nullptr;
GLuint buffer;
GLuint texture;
GLuint displaylist;
@ -1413,51 +1413,62 @@ bool GFX_LazyFullscreenRequested(void) {
return false;
}
bool GFX_StartUpdate(Bit8u * & pixels,Bitu & pitch) {
// This function returns write'able buffer for user to draw upon. Successful
// return depends on properly initialized SDL_Block structure (which generally
// can be achieved via GFX_SetSize call), and specifically - properly initialized
// output-specific bits (sdl.surface, sdl.texture, sdl.opengl.framebuf, or
// sdl.openg.pixel_buffer_object fields).
//
// If everything is prepared correctly, this function returns true, assigns
// 'pixels' output parameter to to a buffer (with format specified via earlier
// GFX_SetSize call), and assigns 'pitch' to a number of bytes used for a single
// pixels row in 'pixels' buffer.
//
bool GFX_StartUpdate(uint8_t * &pixels, int &pitch)
{
if (!sdl.update_display_contents)
return false;
if (!sdl.active || sdl.updating)
return false;
void *tex_pixels = nullptr;
switch (sdl.desktop.type) {
case SCREEN_SURFACE:
pixels = (Bit8u *)sdl.surface->pixels;
pixels = static_cast<uint8_t *>(sdl.surface->pixels);
pixels += sdl.clip.y * sdl.surface->pitch;
pixels += sdl.clip.x * sdl.surface->format->BytesPerPixel;
static_assert(std::is_same<decltype(pitch), decltype((sdl.surface->pitch))>::value,
"SDL internal surface pitch type should match our type.");
pitch = sdl.surface->pitch;
sdl.updating = true;
return true;
case SCREEN_TEXTURE:
{
void * texPixels;
int texPitch;
if (SDL_LockTexture(sdl.texture.texture, NULL, &texPixels, &texPitch) < 0)
if (SDL_LockTexture(sdl.texture.texture, nullptr, &tex_pixels, &pitch) < 0)
return false;
pixels = (Bit8u *)texPixels;
pitch = texPitch;
sdl.updating=true;
pixels = static_cast<uint8_t *>(tex_pixels);
sdl.updating = true;
return true;
}
#if C_OPENGL
case SCREEN_OPENGL:
if(sdl.opengl.pixel_buffer_object) {
glBindBufferARB(GL_PIXEL_UNPACK_BUFFER_EXT, sdl.opengl.buffer);
pixels=(Bit8u *)glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_EXT, GL_WRITE_ONLY);
if (sdl.opengl.pixel_buffer_object) {
glBindBufferARB(GL_PIXEL_UNPACK_BUFFER_EXT, sdl.opengl.buffer);
pixels = static_cast<uint8_t *>(glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_EXT, GL_WRITE_ONLY));
} else {
pixels=(Bit8u *)sdl.opengl.framebuf;
pixels = static_cast<uint8_t *>(sdl.opengl.framebuf);
}
OPENGL_ERROR("end of start update");
if (pixels == NULL) return false;
pitch=sdl.opengl.pitch;
sdl.updating=true;
if (pixels == nullptr)
return false;
static_assert(std::is_same<decltype(pitch), decltype((sdl.opengl.pitch))>::value,
"Our internal pitch types should be the same.");
pitch = sdl.opengl.pitch;
sdl.updating = true;
return true;
#endif
default:
break;
}
return false;
}
void GFX_EndUpdate( const Bit16u *changedLines ) {
if (!sdl.update_display_contents)
return;