qcam: viewfinder_gl: Support configurable stride in shaders

The RGB and YUV conversion doesn't take the stride into account, neither
when creating the textures, nor when sampling them. Fix it by using the
stride as the texture width, and multiplying the x coordinate in the
vertex shaders by a factor to only sample the active portion of the
image.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/qcam/assets/shader/identity.vert b/src/qcam/assets/shader/identity.vert
index 6d6f7551..12c41377 100644
--- a/src/qcam/assets/shader/identity.vert
+++ b/src/qcam/assets/shader/identity.vert
@@ -9,8 +9,10 @@ attribute vec4 vertexIn;
 attribute vec2 textureIn;
 varying vec2 textureOut;
 
+uniform float stride_factor;
+
 void main(void)
 {
 	gl_Position = vertexIn;
-	textureOut = textureIn;
+	textureOut = vec2(textureIn.x * stride_factor, textureIn.y);
 }