[orx-obj-loader] Add obj saver, demos (#348)

orx-obj-loader/src/demo/kotlin/DemoObjLoader01.kt

@@ -0,0 +1,31 @@
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.DepthTestPass
+import org.openrndr.draw.DrawPrimitive
+import org.openrndr.draw.shadeStyle
+import org.openrndr.extra.objloader.loadOBJasVertexBuffer
+import org.openrndr.math.Vector3
+
+fun main() = application {
+    program {
+        val mesh = loadOBJasVertexBuffer("demo-data/obj-models/suzanne/Suzanne.obj")
+
+        extend {
+            drawer.perspective(60.0, width * 1.0 / height, 0.01, 1000.0)
+            drawer.depthWrite = true
+            drawer.depthTestPass = DepthTestPass.LESS_OR_EQUAL
+            drawer.fill = ColorRGBa.PINK
+            drawer.shadeStyle = shadeStyle {
+                fragmentTransform = """
+                        vec3 lightDir = normalize(vec3(0.3, 1.0, 0.5));
+                        float l = dot(va_normal, lightDir) * 0.4 + 0.5;
+                        x_fill.rgb *= l; 
+                    """.trimIndent()
+            }
+            drawer.translate(0.0, 0.0, -2.0)
+            drawer.rotate(Vector3.UNIT_X, -seconds * 2 + 30)
+            drawer.rotate(Vector3.UNIT_Y, -seconds * 15 + 20)
+            drawer.vertexBuffer(mesh, DrawPrimitive.TRIANGLES)
+        }
+    }
+}

orx-obj-loader/src/demo/kotlin/DemoObjSaver01.kt

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+import org.openrndr.application
+import org.openrndr.draw.loadFont
+import org.openrndr.extra.objloader.loadOBJasVertexBuffer
+import org.openrndr.extra.objloader.saveOBJ
+
+fun main() = application {
+    configure {
+        height = 100
+    }
+    program {
+        val path = "demo-data/obj-models"
+        val mesh = loadOBJasVertexBuffer("$path/suzanne/Suzanne.obj")
+        mesh.saveOBJ("$path/Suzanne-exported.obj")
+
+        val font = loadFont("demo-data/fonts/IBMPlexMono-Regular.ttf", 24.0)
+
+        extend {
+            drawer.fontMap = font
+            drawer.text(".obj file loaded and saved", 10.0, 80.0)
+        }
+    }
+}

orx-obj-loader/src/demo/kotlin/DemoObjSaver02.kt

@@ -0,0 +1,35 @@
+import org.openrndr.application
+import org.openrndr.draw.loadFont
+import org.openrndr.extra.meshgenerators.buildTriangleMesh
+import org.openrndr.extra.meshgenerators.sphere
+import org.openrndr.extra.objloader.saveOBJ
+
+fun main() = application {
+    configure {
+        height = 100
+    }
+    program {
+        val path = "demo-data/obj-models/"
+        val mesh = buildTriangleMesh {
+            repeat(4) { x ->
+                repeat(4) { y ->
+                    repeat(4) { z ->
+                        isolated {
+                            translate(x * 1.0, y * 1.0, z * 1.0)
+                            sphere(8, 8,
+                                (x * 91 + y * 79 + z * 17).mod(5) * 0.2 + 0.1)
+                        }
+                    }
+                }
+            }
+        }
+        mesh.saveOBJ("$path/sphere-composition-exported.obj")
+
+        val font = loadFont("demo-data/fonts/IBMPlexMono-Regular.ttf", 24.0)
+
+        extend {
+            drawer.fontMap = font
+            drawer.text("Mesh generated and .obj file saved", 10.0, 80.0)
+        }
+    }
+}