Screen capture demo (#123)

* Add screen capture demo
* Tweak build.gradle ffmpeg dependency

build.gradle

@@ -14,7 +14,7 @@ buildscript {
 apply plugin: 'org.jetbrains.dokka'
 
 project.ext {
-    openrndrVersion = "0.3.43-rc.5"
+    openrndrVersion = "0.3.43-rc.11"
     kotlinVersion = "1.3.72"
     spekVersion = "2.0.10"
     libfreenectVersion = "0.5.7-1.5.3"

openrndr-demos/build.gradle

@@ -13,9 +13,12 @@ def boofcvVersion = "0.34"
 dependencies {
     demoImplementation(project(":orx-mesh-generators"))
     demoImplementation(project(":orx-camera"))
+    demoImplementation(project(":orx-parameters"))
 
     demoImplementation("org.openrndr:openrndr-core:$openrndrVersion")
     demoImplementation("org.openrndr:openrndr-extensions:$openrndrVersion")
+    demoImplementation("org.openrndr:openrndr-ffmpeg:$openrndrVersion")
+    demoRuntimeOnly("org.openrndr:openrndr-ffmpeg-natives-$openrndrOS:$openrndrVersion")
     demoRuntimeOnly("org.openrndr:openrndr-gl3:$openrndrVersion")
     demoRuntimeOnly("org.openrndr:openrndr-gl3-natives-$openrndrOS:$openrndrVersion")
     demoImplementation(sourceSets.getByName("main").output)

openrndr-demos/src/demo/kotlin/DemoScreenCapture01.kt

@@ -0,0 +1,44 @@
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.DepthTestPass
+import org.openrndr.draw.DrawPrimitive
+import org.openrndr.draw.isolated
+import org.openrndr.draw.shadeStyle
+import org.openrndr.extras.meshgenerators.boxMesh
+import org.openrndr.ffmpeg.VideoPlayerFFMPEG
+import org.openrndr.math.Vector3
+
+fun main() {
+    application {
+        program {
+            val cube = boxMesh()
+            val screen = VideoPlayerFFMPEG.fromScreen(
+                frameRate = 15.0,
+                imageWidth = 300,
+                imageHeight = 300
+            )
+
+            screen.play()
+            extend {
+                screen.draw(drawer, true) // update the screen grabber
+                drawer.isolated {
+                    clear(ColorRGBa.WHITE)
+                    perspective(60.0, width * 1.0 / height, 0.01, 1000.0)
+                    depthWrite = true
+                    depthTestPass = DepthTestPass.LESS_OR_EQUAL
+                    shadeStyle = shadeStyle {
+                        fragmentTransform = "x_fill = texture(p_tex, vec2(1.0-va_texCoord0.x, va_texCoord0.y));"
+                        screen.colorBuffer?.run {
+                            parameter("tex", this)
+                        }
+                    }
+                    rotate(Vector3.UNIT_Z, 90.0)
+                    translate(0.0, 0.0, -120.0)
+                    rotate(Vector3.UNIT_X, seconds * 10)
+                    scale(90.0)
+                    vertexBuffer(cube, DrawPrimitive.TRIANGLES)
+                }
+            }
+        }
+    }
+}