shithub: cstory

Info  •  Files  •  Log  •  Branches

Fix text-flickering in the OpenGL renderers

This would occur in CSE2E's options menu.

It was caused by cute_spritebatch destroying a texture atlas that
was being used by the current unflushed vertex buffer. To solve
this, we now track what textures are being used by current buffer,
and flush the buffer when the texture are about to be
modified/deleted.

As you can guess, this issue doesn't affect the SDLTexture backend,
since its batching system is half-decent.

--- a/src/Backends/Rendering/OpenGL3.cpp

+++ b/src/Backends/Rendering/OpenGL3.cpp

@@ -92,6 +92,8 @@

 static unsigned long current_vertex_buffer_slot;

 static RenderMode last_render_mode;

+static GLuint last_source_texture;

+static GLuint last_destination_texture;

 static Backend_Surface framebuffer;

@@ -375,8 +377,6 @@

 // Blit the glyphs in the batch

 static void GlyphBatch_Draw(spritebatch_sprite_t *sprites, int count, int texture_w, int texture_h, void *udata)

 {

-	static Backend_Surface *last_surface;

-	static GLuint last_texture_id;

 	static unsigned char last_red;

 	static unsigned char last_green;

 	static unsigned char last_blue;

@@ -389,13 +389,13 @@

 	GLuint texture_id = (GLuint)sprites[0].texture_id;

 	// Flush vertex data if a context-change is needed

-	if (last_render_mode != MODE_DRAW_GLYPH || last_surface != glyph_destination_surface || last_texture_id != texture_id || last_red != glyph_colour_channels[0] || last_green != glyph_colour_channels[1] || last_blue != glyph_colour_channels[2])

+	if (last_render_mode != MODE_DRAW_GLYPH || last_destination_texture != glyph_destination_surface->texture_id || last_source_texture != texture_id || last_red != glyph_colour_channels[0] || last_green != glyph_colour_channels[1] || last_blue != glyph_colour_channels[2])

 	{

 		FlushVertexBuffer();

 		last_render_mode = MODE_DRAW_GLYPH;

-		last_surface = glyph_destination_surface;

-		last_texture_id = texture_id;

+		last_destination_texture = glyph_destination_surface->texture_id;

+		last_source_texture = texture_id;

 		last_red = glyph_colour_channels[0];

 		last_green = glyph_colour_channels[1];

 		last_blue = glyph_colour_channels[2];

@@ -509,7 +509,13 @@

 {

 	(void)udata;

-	glDeleteTextures(1, (GLuint*)&texture_id);

+	GLuint gl_texture_id = (GLuint)texture_id;

+

+	// Flush the vertex buffer if we're about to destroy its texture

+	if (gl_texture_id == last_source_texture || gl_texture_id == last_destination_texture)

+		FlushVertexBuffer();

+

+	glDeleteTextures(1, &gl_texture_id);

 }

 // ====================

@@ -719,6 +725,8 @@

 {

 	FlushVertexBuffer();

 	last_render_mode = MODE_BLANK;

+	last_source_texture = 0;

+	last_destination_texture = 0;

 	glUseProgram(program_texture);

@@ -819,6 +827,10 @@

 	if (surface == NULL)

 		return;

+	// Flush the vertex buffer if we're about to destroy its texture

+	if (surface->texture_id == last_source_texture || surface->texture_id == last_destination_texture)

+		FlushVertexBuffer();

+

 	glDeleteTextures(1, &surface->texture_id);

 	free(surface);

 }

@@ -850,6 +862,10 @@

 	if (surface == NULL)

 		return;

+	// Flush the vertex buffer if we're about to modify its texture

+	if (surface->texture_id == last_source_texture || surface->texture_id == last_destination_texture)

+		FlushVertexBuffer();

+

 	GLint previously_bound_texture;

 	glGetIntegerv(GL_TEXTURE_BINDING_2D, &previously_bound_texture);

@@ -866,9 +882,6 @@

 void Backend_Blit(Backend_Surface *source_surface, const RECT *rect, Backend_Surface *destination_surface, long x, long y, BOOL colour_key)

 {

-	static Backend_Surface *last_source_surface;

-	static Backend_Surface *last_destination_surface;

-

 	if (source_surface == NULL || destination_surface == NULL)

 		return;

@@ -878,13 +891,13 @@

 	const RenderMode render_mode = (colour_key ? MODE_DRAW_SURFACE_WITH_TRANSPARENCY : MODE_DRAW_SURFACE);

 	// Flush vertex data if a context-change is needed

-	if (last_render_mode != render_mode || last_source_surface != source_surface || last_destination_surface != destination_surface)

+	if (last_render_mode != render_mode || last_source_texture != source_surface->texture_id || last_destination_texture != destination_surface->texture_id)

 	{

 		FlushVertexBuffer();

 		last_render_mode = render_mode;

-		last_source_surface = source_surface;

-		last_destination_surface = destination_surface;

+		last_source_texture = source_surface->texture_id;

+		last_destination_texture = destination_surface->texture_id;

 		// Point our framebuffer to the destination texture

 		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, destination_surface->texture_id, 0);

@@ -945,7 +958,6 @@

 void Backend_ColourFill(Backend_Surface *surface, const RECT *rect, unsigned char red, unsigned char green, unsigned char blue)

 {

-	static Backend_Surface *last_surface;

 	static unsigned char last_red;

 	static unsigned char last_green;

 	static unsigned char last_blue;

@@ -957,12 +969,13 @@

 		return;

 	// Flush vertex data if a context-change is needed

-	if (last_render_mode != MODE_COLOUR_FILL || last_surface != surface || last_red != red || last_green != green || last_blue != blue)

+	if (last_render_mode != MODE_COLOUR_FILL || last_destination_texture != surface->texture_id || last_red != red || last_green != green || last_blue != blue)

 	{

 		FlushVertexBuffer();

 		last_render_mode = MODE_COLOUR_FILL;

-		last_surface = surface;

+		last_source_texture = 0;

+		last_destination_texture = surface->texture_id;

 		last_red = red;

 		last_green = green;

 		last_blue = blue;

-- 

⑨