Does Qt have an additive blend mode?
QPainter has many composition modes but none called additive. I'm interested because additive blending is used all the time in games for lighting / particles whatever.
The overlay mode is the only one that had something like the effect of lighting.
EDIT: I figured it out, heres how you can efficiently make different coloured lights in Qt.
In constructor or where ever, not in paint event:
light = QPixmap("light.png");
QPainter pix(light);
pix.setCompositionMode(QPainter::CompositionMode_Overlay);
pix.fillRect(light.rect(), QColor(255, 0, 0, 255)); // colorize the light in any color
Paint Event:
// Do drawing, e.g. a background
p.drawPixmap(0, 0, QPixmap("background.png"));
// draw the lighting
p.setCompositionMode(QPainter::CompositionMode_Plus);
p.drawPixmap(100, 100, light);
You can reuse the same pixmap as much as you like and draw it with different opacity or size etc.
qt qpainter
edited Dec 8 '18 at 23:43
eyllanesc
79.5k103258
asked Nov 24 '18 at 8:21
nightnight
185
add a comment |
QPainter has many composition modes but none called additive. I'm interested because additive blending is used all the time in games for lighting / particles whatever.
The overlay mode is the only one that had something like the effect of lighting.
EDIT: I figured it out, heres how you can efficiently make different coloured lights in Qt.
In constructor or where ever, not in paint event:
light = QPixmap("light.png");
QPainter pix(light);
pix.setCompositionMode(QPainter::CompositionMode_Overlay);
pix.fillRect(light.rect(), QColor(255, 0, 0, 255)); // colorize the light in any color
Paint Event:
// Do drawing, e.g. a background
p.drawPixmap(0, 0, QPixmap("background.png"));
// draw the lighting
p.setCompositionMode(QPainter::CompositionMode_Plus);
p.drawPixmap(100, 100, light);
You can reuse the same pixmap as much as you like and draw it with different opacity or size etc.
qt qpainter
edited Dec 8 '18 at 23:43
eyllanesc
79.5k103258
asked Nov 24 '18 at 8:21
nightnight
185
add a comment |
QPainter has many composition modes but none called additive. I'm interested because additive blending is used all the time in games for lighting / particles whatever.
The overlay mode is the only one that had something like the effect of lighting.
EDIT: I figured it out, heres how you can efficiently make different coloured lights in Qt.
In constructor or where ever, not in paint event:
light = QPixmap("light.png");
QPainter pix(light);
pix.setCompositionMode(QPainter::CompositionMode_Overlay);
pix.fillRect(light.rect(), QColor(255, 0, 0, 255)); // colorize the light in any color
Paint Event:
// Do drawing, e.g. a background
p.drawPixmap(0, 0, QPixmap("background.png"));
// draw the lighting
p.setCompositionMode(QPainter::CompositionMode_Plus);
p.drawPixmap(100, 100, light);
You can reuse the same pixmap as much as you like and draw it with different opacity or size etc.
qt qpainter
edited Dec 8 '18 at 23:43
eyllanesc
79.5k103258
asked Nov 24 '18 at 8:21
nightnight
185
QPainter has many composition modes but none called additive. I'm interested because additive blending is used all the time in games for lighting / particles whatever.
The overlay mode is the only one that had something like the effect of lighting.
EDIT: I figured it out, heres how you can efficiently make different coloured lights in Qt.
In constructor or where ever, not in paint event:
light = QPixmap("light.png");
QPainter pix(light);
pix.setCompositionMode(QPainter::CompositionMode_Overlay);
pix.fillRect(light.rect(), QColor(255, 0, 0, 255)); // colorize the light in any color
Paint Event:
// Do drawing, e.g. a background
p.drawPixmap(0, 0, QPixmap("background.png"));
// draw the lighting
p.setCompositionMode(QPainter::CompositionMode_Plus);
p.drawPixmap(100, 100, light);
You can reuse the same pixmap as much as you like and draw it with different opacity or size etc.
qt qpainter
qt qpainter
edited Dec 8 '18 at 23:43
eyllanesc
79.5k103258
asked Nov 24 '18 at 8:21
nightnight
185
edited Dec 8 '18 at 23:43
eyllanesc
79.5k103258
asked Nov 24 '18 at 8:21
nightnight
185
edited Dec 8 '18 at 23:43
eyllanesc
79.5k103258
edited Dec 8 '18 at 23:43
eyllanesc
79.5k103258
edited Dec 8 '18 at 23:43
eyllanesc
79.5k103258
79.5k103258
asked Nov 24 '18 at 8:21
nightnight
185
asked Nov 24 '18 at 8:21
nightnight
185
asked Nov 24 '18 at 8:21
nightnight
185
185
add a comment |
add a comment |
1 Answer
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oldest
votes
The documentation for QPainter::CompositionMode_Plus says:
Both the alpha and color of the source and destination pixels are added together.
answered Nov 24 '18 at 18:07
Jason HaslamJason Haslam
1,318614
Yeah. I think thats it. They should say aka additive mode in the documentation. I figured out how to make everything blend together the way I wanted.
– night
Nov 24 '18 at 23:06
add a comment |
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1 Answer
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1 Answer
1
active
oldest
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active
oldest
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active
oldest
votes
The documentation for QPainter::CompositionMode_Plus says:
Both the alpha and color of the source and destination pixels are added together.
answered Nov 24 '18 at 18:07
Jason HaslamJason Haslam
1,318614
Yeah. I think thats it. They should say aka additive mode in the documentation. I figured out how to make everything blend together the way I wanted.
– night
Nov 24 '18 at 23:06
add a comment |
The documentation for QPainter::CompositionMode_Plus says:
Both the alpha and color of the source and destination pixels are added together.
answered Nov 24 '18 at 18:07
Jason HaslamJason Haslam
1,318614
Yeah. I think thats it. They should say aka additive mode in the documentation. I figured out how to make everything blend together the way I wanted.
– night
Nov 24 '18 at 23:06
add a comment |
The documentation for QPainter::CompositionMode_Plus says:
Both the alpha and color of the source and destination pixels are added together.
answered Nov 24 '18 at 18:07
Jason HaslamJason Haslam
1,318614
The documentation for QPainter::CompositionMode_Plus says:
Both the alpha and color of the source and destination pixels are added together.
answered Nov 24 '18 at 18:07
Jason HaslamJason Haslam
1,318614
answered Nov 24 '18 at 18:07
Jason HaslamJason Haslam
1,318614
answered Nov 24 '18 at 18:07
Jason HaslamJason Haslam
1,318614
answered Nov 24 '18 at 18:07
Jason HaslamJason Haslam
1,318614
1,318614
Yeah. I think thats it. They should say aka additive mode in the documentation. I figured out how to make everything blend together the way I wanted.
– night
Nov 24 '18 at 23:06
add a comment |
Yeah. I think thats it. They should say aka additive mode in the documentation. I figured out how to make everything blend together the way I wanted.
– night
Nov 24 '18 at 23:06
Yeah. I think thats it. They should say aka additive mode in the documentation. I figured out how to make everything blend together the way I wanted.
– night
Nov 24 '18 at 23:06
Yeah. I think thats it. They should say aka additive mode in the documentation. I figured out how to make everything blend together the way I wanted.
– night
Nov 24 '18 at 23:06
add a comment |
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