RenderPass QML Type

Defines a custom render pass for rendering 3D content. More...

• List of all members, including inherited members

Properties

• augmentShader : url
• clearColor : color
• commands : list<RenderCommand>
• depthClearValue : real
• materialMode : RenderPass::MaterialModes
• overrideMaterial : Material
• passMode : RenderPass::PassMode
• renderTargetFlags : RenderPass::RenderTargetFlags
• stencilClearValue : int

Detailed Description

A RenderPass defines a rendering step and the render target it writes into. It is the combination of three concerns:

• Where to render — one or more output textures declared as ColorAttachment or DepthTextureAttachment commands in commands.
• What to render — which scene objects the pass draws, controlled by RenderablesFilter commands. Sub-divisions of work within the same render target are described using SubRenderPass commands.
• How to render — the materialMode and any PipelineStateOverride commands.

A RenderPass becomes active for a scene when it is placed as a child of a View3D or a Node.

The following example sets up a simple off-screen pass that renders all scene objects into a custom texture, which can then be consumed by a material or a SimpleQuadRenderer:

import QtQuick3D

View3D {
    // Declare the off-screen color buffer
    RenderPassTexture {
        id: myColorTexture
        format: RenderPassTexture.RGBA8
    }

    // The render pass: where + what + how
    RenderPass {
        id: myRenderPass
        commands: [
            // Where: attach the texture as the color output
            ColorAttachment {
                name: "color0"
                target: myColorTexture
            },
            // What: render all objects into it
            RenderablesFilter {
                renderableTypes: RenderablesFilter.Opaque | RenderablesFilter.Transparent
            }
        ]
    }
}

Exposing data to the shaders

As with Effects and Custom Materials, the RenderPass will expose and update user-defined properties to the shaders automatically. Any QML properties declared on a RenderPass subtype will be available as uniforms in the shader.

See also SubRenderPass, RenderOutputProvider, and RenderablesFilter.

Property Documentation

augmentShader : url

This property holds the augment shader URL for the render pass when materialMode is set to AugmentMaterial.

The shader file should contain a function with the following signature:

void MAIN_FRAGMENT_AUGMENT() {
    // Custom shader code here
}

This function will be combined with the existing fragment shader of the material being used by the object being rendered in this render pass. Allowing users to augment the existing material shader with custom code.

clearColor : color [default: Qt.black]

This property holds the clear color for the render pass.

commands : list<RenderCommand>

This property holds the list of render commands for the render pass.

The commands in the list are executed in the order they appear in the list.

See also SubRenderPass, PipelineStateOverride, RenderablesFilter, RenderPassTexture, ColorAttachment, DepthTextureAttachment, DepthStencilAttachment, AddDefine, and renderTargetBlend.

depthClearValue : real [default: 1.0]

This property holds the depth clear value for the render pass.

materialMode : RenderPass::MaterialModes [default: RenderPass.OriginalMaterial]

Controls how object materials are handled when rendering into this pass.

overrideMaterial : Material

This property holds the override material for the render pass when materialMode is set to OverrideMaterial.

passMode : RenderPass::PassMode [default: RenderPass.UserPass]

This property holds the pass mode for the render pass.

In addition to standard user render passes, Qt Quick 3D supports users to manually triggering internal render passes for rendering the skybox and 2D items.

renderTargetFlags : RenderPass::RenderTargetFlags [default: RenderPass.None]

This property holds the render target flags for the render pass. These flags affect how the render target contents are handled at the beginning and end of each frame.

See also QRhiTextureRenderTarget::Flags.

stencilClearValue : int [default: 0]

This property holds the stencil clear value for the render pass.