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Draw image mirror options

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I have some image effect and i need the X mirror version so i need to create a second texture.

 

Context Draw image would be great to have image options like :

- mirror X

- mirror Y

- scaling

Why not rotate ?

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Context:DrawImage() already gives you the ability to scale the image. For mirrored images, you just need to use the negative of the image's vertex X and/or Y coords. Rotating an image requires a little more shader programming - I have used this several times myself as shown here: http://www.leadwerks.com/werkspace/page/viewitem?fileid=317982413

 

A modified drawimage shader that does what you are asking for:

drawimage_enhanced.zip

 

Example of how to use:

window = Window:Create("draw mirrored or rotated image",0,0,800,600)

context = Context:Create(window)

 

imageshader = Shader:Load("Shaders/Drawing/drawimage_enhanced.shader")

image = Texture:Load("Materials/Developer/leadwerks.tex")

angle = 0

 

while window:KeyDown(Key.Escape)==false do

angle = angle +1

 

context:SetColor(1,0,1)

context:Clear()

context:SetColor(1,1,1)

 

oldshader = context:GetShader() -- capture default context shader

context:SetShader(imageshader) -- set the image shader

 

imageshader:SetFloat("angle", 0) -- set angle to default

imageshader:SetVec2("pivotposition", Vec2(0.0,0.0)) -- set pivot to default

imageshader:SetInt("flip", 0) -- set flip to default

context:DrawImage(image,0,0,400,300) -- draw normal image

 

imageshader:SetInt("flip", 3) -- mirror in X&Y

context:DrawImage(image,400,300,400,300) --draw flipped image

 

imageshader:SetFloat("angle", angle) -- set varying angle

imageshader:SetVec2("pivotposition", Vec2(100.0,100.0)) --set pivot to center of image

imageshader:SetInt("flip", 0) -- set flip for normal drawing

context:DrawImage(image,300,200,200,200) -- draw rotating image

 

context:SetShader(oldshader) -- set back to default context shader

 

context:Sync(true)

end

 

Options for "flip":

  • 0 = normal
  • 1 = X flipped
  • 2 = Y flipped
  • 3 = X & Y flipped

 

Note: use un-clamped textures if flipping the image with this shader.

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