OpenTTD Source  20241108-master-g80f628063a
OpenGLBackend Class Reference

Platform-independent back-end class for OpenGL video drivers. More...

#include <opengl.h>

Inheritance diagram for OpenGLBackend:
ZeroedMemoryAllocator SpriteEncoder

Public Member Functions

void PrepareContext ()
 
std::string GetDriverName ()
 
void UpdatePalette (const Colour *pal, uint first, uint length)
 Update the stored palette. More...
 
bool Resize (int w, int h, bool force=false)
 Change the size of the drawing window and allocate matching resources. More...
 
void Paint ()
 Render video buffer to the screen.
 
void DrawMouseCursor ()
 Draw mouse cursor on screen.
 
void PopulateCursorCache ()
 
void ClearCursorCache ()
 Queue a request for cursor cache clear.
 
void * GetVideoBuffer ()
 Get a pointer to the memory for the video driver to draw to. More...
 
uint8_t * GetAnimBuffer ()
 Get a pointer to the memory for the separate animation buffer. More...
 
void ReleaseVideoBuffer (const Rect &update_rect)
 Update video buffer texture after the video buffer was filled. More...
 
void ReleaseAnimBuffer (const Rect &update_rect)
 Update animation buffer texture after the animation buffer was filled. More...
 
bool Is32BppSupported () override
 Can the sprite encoder make use of RGBA sprites?
 
uint GetSpriteAlignment () override
 Get the value which the height and width on a sprite have to be aligned by. More...
 
SpriteEncode (const SpriteLoader::SpriteCollection &sprite, SpriteAllocator &allocator) override
 Convert a sprite from the loader to our own format.
 
- Public Member Functions inherited from ZeroedMemoryAllocator
void * operator new (size_t size)
 Memory allocator for a single class instance. More...
 
void * operator new[] (size_t size)
 Memory allocator for an array of class instances. More...
 
void operator delete (void *ptr)
 Memory release for a single class instance. More...
 
void operator delete[] (void *ptr)
 Memory release for an array of class instances. More...
 

Static Public Member Functions

static OpenGLBackendGet ()
 Get singleton instance of this class.
 
static std::optional< std::string_view > Create (GetOGLProcAddressProc get_proc, const Dimension &screen_res)
 Create and initialize the singleton back-end class. More...
 
static void Destroy ()
 Free resources and destroy singleton back-end class.
 

Private Member Functions

 OpenGLBackend ()
 Construct OpenGL back-end class.
 
 ~OpenGLBackend ()
 Free allocated resources.
 
std::optional< std::string_view > Init (const Dimension &screen_res)
 Check for the needed OpenGL functionality and allocate all resources. More...
 
bool InitShaders ()
 Create all needed shader programs. More...
 
void InternalClearCursorCache ()
 Clear all cached cursor sprites.
 
void RenderOglSprite (OpenGLSprite *gl_sprite, PaletteID pal, int x, int y, ZoomLevel zoom)
 Render a sprite to the back buffer. More...
 

Private Attributes

bool persistent_mapping_supported
 Persistent pixel buffer mapping supported.
 
GLsync sync_vid_mapping
 Sync object for the persistently mapped video buffer.
 
GLsync sync_anim_mapping
 Sync object for the persistently mapped animation buffer.
 
void * vid_buffer
 Pointer to the mapped video buffer.
 
GLuint vid_pbo
 Pixel buffer object storing the memory used for the video driver to draw to.
 
GLuint vid_texture
 Texture handle for the video buffer texture.
 
GLuint vid_program
 Shader program for rendering a RGBA video buffer.
 
GLuint pal_program
 Shader program for rendering a paletted video buffer.
 
GLuint vao_quad
 Vertex array object storing the rendering state for the fullscreen quad.
 
GLuint vbo_quad
 Vertex buffer with a fullscreen quad.
 
GLuint pal_texture
 Palette lookup texture.
 
void * anim_buffer
 Pointer to the mapped animation buffer.
 
GLuint anim_pbo
 Pixel buffer object storing the memory used for the animation buffer.
 
GLuint anim_texture
 Texture handle for the animation buffer texture.
 
GLuint remap_program
 Shader program for blending and rendering a RGBA + remap texture.
 
GLint remap_sprite_loc
 Uniform location for sprite parameters.
 
GLint remap_screen_loc
 Uniform location for screen size.
 
GLint remap_zoom_loc
 Uniform location for sprite zoom.
 
GLint remap_rgb_loc
 Uniform location for RGB mode flag.
 
GLuint sprite_program
 Shader program for blending and rendering a sprite to the video buffer.
 
GLint sprite_sprite_loc
 Uniform location for sprite parameters.
 
GLint sprite_screen_loc
 Uniform location for screen size.
 
GLint sprite_zoom_loc
 Uniform location for sprite zoom.
 
GLint sprite_rgb_loc
 Uniform location for RGB mode flag.
 
GLint sprite_crash_loc
 Uniform location for crash remap mode flag.
 
LRUCache< SpriteID, Spritecursor_cache
 Cache of encoded cursor sprites.
 
PaletteID last_sprite_pal = (PaletteID)-1
 Last uploaded remap palette.
 
bool clear_cursor_cache = false
 A clear of the cursor cache is pending.
 
Point cursor_pos
 Cursor position.
 
bool cursor_in_window
 Cursor inside this window.
 
std::vector< CursorSpritecursor_sprites
 Sprites comprising cursor.
 

Static Private Attributes

static OpenGLBackendinstance = nullptr
 Singleton instance pointer.
 

Detailed Description

Platform-independent back-end class for OpenGL video drivers.

Definition at line 28 of file opengl.h.

Member Function Documentation

◆ Create()

std::optional< std::string_view > OpenGLBackend::Create ( GetOGLProcAddressProc  get_proc,
const Dimension screen_res 
)
static

Create and initialize the singleton back-end class.

Parameters
get_procCallback to get an OpenGL function from the OS driver.
screen_resCurrent display resolution.
Returns
std::nullopt on success, error message otherwise.

Definition at line 467 of file opengl.cpp.

◆ GetAnimBuffer()

uint8_t * OpenGLBackend::GetAnimBuffer ( )

Get a pointer to the memory for the separate animation buffer.

Returns
Pointer to draw on.

Definition at line 1170 of file opengl.cpp.

References anim_buffer, anim_pbo, persistent_mapping_supported, and sync_anim_mapping.

Referenced by VideoDriver_SDL_OpenGL::GetVideoPointer().

◆ GetSpriteAlignment()

uint OpenGLBackend::GetSpriteAlignment ( )
inlineoverridevirtual

Get the value which the height and width on a sprite have to be aligned by.

Returns
The needed alignment or 0 if any alignment is accepted.

Reimplemented from SpriteEncoder.

Definition at line 109 of file opengl.h.

References ZOOM_LVL_END.

◆ GetVideoBuffer()

void * OpenGLBackend::GetVideoBuffer ( )

Get a pointer to the memory for the video driver to draw to.

Returns
Pointer to draw on.

Definition at line 1148 of file opengl.cpp.

References persistent_mapping_supported, sync_vid_mapping, vid_buffer, and vid_pbo.

Referenced by VideoDriver_SDL_OpenGL::GetVideoPointer().

◆ Init()

std::optional< std::string_view > OpenGLBackend::Init ( const Dimension screen_res)
private

Check for the needed OpenGL functionality and allocate all resources.

Parameters
screen_resCurrent display resolution.
Returns
Error string or std::nullopt if successful.

Definition at line 525 of file opengl.cpp.

References anim_pbo, anim_texture, Debug, InitShaders(), IsOpenGLVersionAtLeast(), pal_program, pal_texture, persistent_mapping_supported, remap_program, remap_rgb_loc, remap_screen_loc, remap_sprite_loc, remap_zoom_loc, sprite_crash_loc, sprite_program, sprite_rgb_loc, sprite_screen_loc, sprite_sprite_loc, sprite_zoom_loc, vao_quad, vbo_quad, vid_pbo, vid_program, and vid_texture.

◆ InitShaders()

◆ ReleaseAnimBuffer()

void OpenGLBackend::ReleaseAnimBuffer ( const Rect update_rect)

Update animation buffer texture after the animation buffer was filled.

Parameters
update_rectRectangle encompassing the dirty region of the animation buffer.

Definition at line 1231 of file opengl.cpp.

References anim_buffer, anim_pbo, anim_texture, persistent_mapping_supported, and sync_anim_mapping.

Referenced by VideoDriver_SDL_OpenGL::ReleaseVideoPointer().

◆ ReleaseVideoBuffer()

void OpenGLBackend::ReleaseVideoBuffer ( const Rect update_rect)

Update video buffer texture after the video buffer was filled.

Parameters
update_rectRectangle encompassing the dirty region of the video buffer.

Definition at line 1193 of file opengl.cpp.

References IsEmptyRect(), persistent_mapping_supported, sync_vid_mapping, vid_buffer, vid_pbo, and vid_texture.

Referenced by VideoDriver_SDL_OpenGL::ReleaseVideoPointer().

◆ RenderOglSprite()

void OpenGLBackend::RenderOglSprite ( OpenGLSprite gl_sprite,
PaletteID  pal,
int  x,
int  y,
ZoomLevel  zoom 
)
private

Render a sprite to the back buffer.

Parameters
gl_spriteSprite to render.
xX position of the sprite.
yY position of the sprite.
zoomZoom level to use.

Definition at line 1289 of file opengl.cpp.

◆ Resize()

bool OpenGLBackend::Resize ( int  w,
int  h,
bool  force = false 
)

Change the size of the drawing window and allocate matching resources.

Parameters
wNew width of the window.
hNew height of the window.
forceRecreate resources even if size didn't change.
Falseif nothing had to be done, true otherwise.

Definition at line 913 of file opengl.cpp.

◆ UpdatePalette()

void OpenGLBackend::UpdatePalette ( const Colour pal,
uint  first,
uint  length 
)

Update the stored palette.

Parameters
palPalette array with at least 256 elements.
firstFirst entry to update.
lengthNumber of entries to update.

Definition at line 1025 of file opengl.cpp.

References pal_texture.

Referenced by VideoDriver_SDL_OpenGL::Paint().


The documentation for this class was generated from the following files: