Files
orx/orx-mesh-generators/src/jvmDemo/kotlin/tangents/DemoTangents01.kt
2025-11-22 19:08:30 +01:00

51 lines
1.8 KiB
Kotlin

package tangents
import org.openrndr.application
import org.openrndr.draw.DrawPrimitive
import org.openrndr.draw.shadeStyle
import org.openrndr.extra.camera.Orbital
import org.openrndr.extra.mesh.toVertexBuffer
import org.openrndr.extra.meshgenerators.tangents.estimateTangents
import org.openrndr.extra.objloader.loadOBJMeshData
import org.openrndr.math.Vector3
import java.io.File
/**
* Tangent and bitangent vectors are used in shader programs for tangent space normal mapping / lighting
* and certain forms of displacement mapping.
*
* This demo shows:
* - how to create a triangulated `MeshData`.
* - how to estimate the tangents of this MeshData.
* - How to use the tangent and bitangent attributes in GLSL code.
*/
fun main() = application {
configure {
width = 720
height = 720
}
program {
val obj = loadOBJMeshData(File("demo-data/obj-models/suzanne/Suzanne.obj")).toMeshData().triangulate()
val tangentObj = obj.estimateTangents()
val objVB = tangentObj.toVertexBuffer()
extend(Orbital()) {
eye = Vector3(0.0, 0.0, 2.0)
}
extend {
drawer.shadeStyle = shadeStyle {
fragmentTransform = """
vec3 viewTangent = (u_viewNormalMatrix * u_modelNormalMatrix * vec4(va_tangent, 0.0)).xyz;
vec3 viewBitangent = (u_viewNormalMatrix * u_modelNormalMatrix * vec4(va_bitangent, 0.0)).xyz;
float c = cos(100.0 * dot(v_worldPosition, va_normal)) * 0.5 + 0.5;
//x_fill.rgb = normalize(viewTangent) * 0.5 + 0.5;
x_fill.rgb = vec3(c);
""".trimIndent()
}
drawer.vertexBuffer(objVB, DrawPrimitive.TRIANGLES)
}
}
}