Make alpha 1.0 when using texscreen, fixes #25850

drivers/gles2/rasterizer_canvas_gles2.cpp

@@ -112,11 +112,11 @@ void RasterizerCanvasGLES2::_set_uniforms() {
 void RasterizerCanvasGLES2::canvas_begin() {
 
 	state.canvas_shader.bind();
-	bool transparent = false;
+	state.using_transparent_rt = false;
 	if (storage->frame.current_rt) {
 		glBindFramebuffer(GL_FRAMEBUFFER, storage->frame.current_rt->fbo);
 		glColorMask(1, 1, 1, 1);
-		transparent = storage->frame.current_rt->flags[RasterizerStorage::RENDER_TARGET_TRANSPARENT];
+		state.using_transparent_rt = storage->frame.current_rt->flags[RasterizerStorage::RENDER_TARGET_TRANSPARENT];
 	}
 
 	if (storage->frame.clear_request) {
@@ -124,12 +124,12 @@ void RasterizerCanvasGLES2::canvas_begin() {
 		glClearColor(storage->frame.clear_request_color.r,
 				storage->frame.clear_request_color.g,
 				storage->frame.clear_request_color.b,
-				transparent ? storage->frame.clear_request_color.a : 1.0);
+				state.using_transparent_rt ? storage->frame.clear_request_color.a : 1.0);
 		glClear(GL_COLOR_BUFFER_BIT);
 		storage->frame.clear_request = false;
 	}
 
-	glColorMask(1, 1, 1, transparent ? 1 : 0);
+	glColorMask(1, 1, 1, state.using_transparent_rt ? 1 : 0);
 
 	/*
 	if (storage->frame.current_rt) {
@@ -186,7 +186,10 @@ void RasterizerCanvasGLES2::canvas_end() {
 	state.using_texture_rect = false;
 	state.using_skeleton = false;
 	state.using_ninepatch = false;
-	glColorMask(1, 1, 1, 1);
+	if (state.using_transparent_rt) {
+		glColorMask(1, 1, 1, 1);
+	}
+	state.using_transparent_rt = false;
 }
 
 RasterizerStorageGLES2::Texture *RasterizerCanvasGLES2::_bind_canvas_texture(const RID &p_texture, const RID &p_normal_map) {
@@ -1179,6 +1182,10 @@ void RasterizerCanvasGLES2::_copy_screen(const Rect2 &p_rect) {
 		ERR_FAIL();
 	}
 
+	if (state.using_transparent_rt) {
+		glColorMask(1, 1, 1, 1);
+	}
+
 	glDisable(GL_BLEND);
 
 	Vector2 wh(storage->frame.current_rt->width, storage->frame.current_rt->height);
@@ -1189,6 +1196,8 @@ void RasterizerCanvasGLES2::_copy_screen(const Rect2 &p_rect) {
 		storage->shaders.copy.set_conditional(CopyShaderGLES2::USE_COPY_SECTION, true);
 	}
 
+	storage->shaders.copy.set_conditional(CopyShaderGLES2::USE_NO_ALPHA, !state.using_transparent_rt);
+
 	glBindFramebuffer(GL_FRAMEBUFFER, storage->frame.current_rt->copy_screen_effect.fbo);
 	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, storage->frame.current_rt->color);
@@ -1218,6 +1227,11 @@ void RasterizerCanvasGLES2::_copy_screen(const Rect2 &p_rect) {
 	_draw_polygon(indexpos, 6, 4, vertpos, uvpos, NULL, false);
 
 	storage->shaders.copy.set_conditional(CopyShaderGLES2::USE_COPY_SECTION, false);
+	storage->shaders.copy.set_conditional(CopyShaderGLES2::USE_NO_ALPHA, false);
+
+	if (state.using_transparent_rt) {
+		glColorMask(1, 1, 1, 0);
+	}
 
 	glBindFramebuffer(GL_FRAMEBUFFER, storage->frame.current_rt->fbo); //back to front
 	glEnable(GL_BLEND);
@@ -2008,6 +2022,7 @@ void RasterizerCanvasGLES2::initialize() {
 	state.canvas_shader.set_conditional(CanvasShaderGLES2::USE_PIXEL_SNAP, GLOBAL_DEF("rendering/quality/2d/use_pixel_snap", false));
 
 	state.using_light = NULL;
+	state.using_transparent_rt = false;
 }
 
 void RasterizerCanvasGLES2::finalize() {

drivers/gles2/rasterizer_canvas_gles2.h

@@ -93,6 +93,7 @@ public:
 		Transform vp;
 		Light *using_light;
 		bool using_shadow;
+		bool using_transparent_rt;
 
 	} state;