[Scummvm-git-logs] scummvm master -> 6342045cc3e23dc9f685241d89ad3da478885f70

[lephilousophe]

This automated email contains information about 1 new commit which have been
pushed to the 'scummvm' repo located at https://github.com/scummvm/scummvm .

Summary:
6342045cc3 BACKENDS: OPENGL: Don't take the alpha channel from the game texture


Commit: 6342045cc3e23dc9f685241d89ad3da478885f70
    https://github.com/scummvm/scummvm/commit/6342045cc3e23dc9f685241d89ad3da478885f70
Author: Le Philousophe (lephilousophe at users.noreply.github.com)
Date: 2024-02-24T16:43:14+01:00

Commit Message:
BACKENDS: OPENGL: Don't take the alpha channel from the game texture

It's not always set correctly by engines (AGS) and a fill call to clear
the screen will set it to 0 along with the other components.
Setting the framebuffer to some transparent value is not something we
intend to do as this let the content underneath the drawing texture
visible like it's the case on ChromeOS.
This has been reported here: https://forums.scummvm.org/viewtopic.php?p=99293

Changed paths:
    backends/graphics/opengl/framebuffer.cpp
    backends/graphics/opengl/framebuffer.h
    backends/graphics/opengl/opengl-graphics.cpp


diff --git a/backends/graphics/opengl/framebuffer.cpp b/backends/graphics/opengl/framebuffer.cpp
index c74ee60ef79..d6b69079f76 100644
--- a/backends/graphics/opengl/framebuffer.cpp
+++ b/backends/graphics/opengl/framebuffer.cpp
@@ -111,6 +111,11 @@ void Framebuffer::applyBlendState() {
 		case kBlendModeDisabled:
 			GL_CALL(glDisable(GL_BLEND));
 			break;
+		case kBlendModeOpaque:
+			GL_CALL(glEnable(GL_BLEND));
+			GL_CALL(glBlendColor(1.f, 1.f, 1.f, 0.f));
+			GL_CALL(glBlendFunc(GL_CONSTANT_COLOR, GL_ONE_MINUS_CONSTANT_COLOR));
+			break;
 		case kBlendModeTraditionalTransparency:
 			GL_CALL(glEnable(GL_BLEND));
 			GL_CALL(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));
diff --git a/backends/graphics/opengl/framebuffer.h b/backends/graphics/opengl/framebuffer.h
index a38663107b1..406a6f983a0 100644
--- a/backends/graphics/opengl/framebuffer.h
+++ b/backends/graphics/opengl/framebuffer.h
@@ -42,10 +42,16 @@ public:
 	enum BlendMode {
 		/**
 		 * Newly drawn pixels overwrite the existing contents of the framebuffer
-		 * without mixing with them
+		 * without mixing with them.
 		 */
 		kBlendModeDisabled,
 
+		/**
+		 * Newly drawn pixels overwrite the existing contents of the framebuffer
+		 * without mixing with them. Alpha channel is discarded.
+		 */
+		kBlendModeOpaque,
+
 		/**
 		 * Newly drawn pixels mix with the framebuffer based on their alpha value
 		 * for transparency.
diff --git a/backends/graphics/opengl/opengl-graphics.cpp b/backends/graphics/opengl/opengl-graphics.cpp
index 4c9970f722b..56d5b970d14 100644
--- a/backends/graphics/opengl/opengl-graphics.cpp
+++ b/backends/graphics/opengl/opengl-graphics.cpp
@@ -700,7 +700,7 @@ void OpenGLGraphicsManager::updateScreen() {
 	bool drawCursor = _cursorVisible && _cursor;
 
 	// Alpha blending is disabled when drawing the screen
-	_targetBuffer->enableBlend(Framebuffer::kBlendModeDisabled);
+	_targetBuffer->enableBlend(Framebuffer::kBlendModeOpaque);
 
 	// First step: Draw the (virtual) game screen.
 	_pipeline->drawTexture(_gameScreen->getGLTexture(), _gameDrawRect.left, _gameDrawRect.top, _gameDrawRect.width(), _gameDrawRect.height());