Qt Quick 3D 自定义材质参考

This page explains how to write custom material using the QtQuick3D .Materials material library interface.

概述

The material specification lets you write custom materials and connect those to the lighting system. Each material must have a fragment shader that implements all the functions the library needs to calculate the shaded color. The material system also offers ready-made functions to help implementing the material. These functions can be accessed by the shader using #include directive with the name of the function.

The material system supports dielectric and transparent materials, point lights, area lights, ambient occlusion, shadowing, two-sided polygons, index-of-refraction, and fragment cutoff (masking).

It is also possible to write custom material without using the boilerplate code, in which case the main function must be implemented in the shader.

要求函数

These are the functions each fragment shader must implement.

bool evalTwoSided()
					

This function controls two-sided lighting. Return true to enable two-sided lighting and false to disable it. When two-sided lighting is disabled, only the front-facing material functions are called.

float computeIOR()
					

This function is called to compute the index of refraction for the material. Return material index of refraction.

float evalCutout()
					

This function is called when evaluating fragment cutoff (masking) value. The fragment is discarded if the value returned by this function is less than or equal to zero.

vec3 computeNormal()
					

This function is used to calculate the normal for the fragment. Return the normal of the fragment.

void computeTemporaries()
					

This function is called to calculate any temporary values needed by the material and it is called before any other function.

void initializeLayerVariables()
					

This function is called to initialize layer parameters for the material. User should initialize variables to store the lighting values to be computed in the computeFrontLayerColor , computeFrontAreaColor , computeFrontLayerEnvironment , computeBackLayerColor , computeBackAreaColor ，和 computeBackLayerEnvironment .

void initializeLayerVariablesWithLightmap()
					

This function is called to allow the material to initialize layer parameters.

注意： This function is optional and gets called only if the material uses lightmaps.

vec3 computeFrontMaterialEmissive()
					

This function is called when the material calculates the Emissive component of the material for the front-facing polygon. Return vec3 RGB emissive value.

vec3 computeBackMaterialEmissive()
					

This function is called when the material calculates the Emissive component of the material for the back-facing polygon. Return vec3 RGB emissive value.

void computeFrontLayerColor( in vec3 normal, in vec3 lightDir, in vec3 viewDir,
                             in vec3 lightDiffuse, in vec3 lightSpecular,
                             in float materialIOR, in float aoFactor )
					

This function is called for every light (excluding area lights) for the front-facing polygon. The material can write its own lighting model or use the provided functions. The functions available for use are microfacetBSDF , physGlossyBSDF ，和 simpleGlossyBSDF 。 normal is the fragment normal. The lightDir is the normalized vector from fragment to light in world space.

void computeFrontAreaColor( in int lightIdx, in vec4 lightDiffuse, in vec4 lightSpecular )
					

This function is called for every area light for the front-facing polygon.

void computeFrontLayerEnvironment( in vec3 normal, in vec3 viewDir, in float aoFactor )
					

This function is called once to calculate the environmental light for the front-facing polygon.

void computeBackLayerColor( in vec3 normal, in vec3 lightDir, in vec3 viewDir,
                            in vec3 lightDiffuse, in vec3 lightSpecular,
                            in float materialIOR, in float aoFactor )
					

This function is called for every light (excluding area lights) for the back-facing polygon. The material can write its own lighting model or use the provided functions. The functions available for use are microfacetBSDF , physGlossyBSDF and simpleGlossyBSDF 。 normal is the fragment normal. The lightDir is the normalized vector from fragment to light in world space.

void computeBackAreaColor( in int lightIdx, in vec4 lightDiffuse, in vec4 lightSpecular )
					

This function is called for every area light for the back-facing polygon.

void computeBackLayerEnvironment( in vec3 normal, in vec3 viewDir, in float aoFactor )
					

This function is called once to calculate the environmental light for the back-facing polygon.

vec4 computeLayerWeights( in float alpha )
					

This function is called after all lighting have been processed to calculate the final lighting value for the fragment.

vec4 computeGlass( in vec3 normal, in float materialIOR, in float alpha, in vec4 color )
					

This function is called only if the material is transparent and non-transmissive after computeLayerWeights has been called.

vec4 computeOpacity( in vec4 color )
					

This function is called only if the material is transmissive after computeLayerWeights has been called.

强制性包括

#include "vertexFragmentBase.glsllib"
#include "SSAOCustomMaterial.glsllib"
#include "sampleLight.glsllib"
#include "sampleProbe.glsllib"
#include "sampleArea.glsllib"
					

These includes are required for all materials.

全局变量

These variables are available to the material, but should not be modified:

vec3 normal;
vec3 surfNormal;
vec3 texCoord0;
vec3 tangent;
vec3 binormal;
vec3 viewDir;
					

These are read-only the fragment shader input variables.

vec3 varTexCoord0;
vec3 varTexCoord1;
vec3 varNormal;
vec3 varTangent;
vec3 varBinormal;
vec3 varObjTangent;
vec3 varObjBinormal;
vec3 varWorldPos;
vec3 varObjPos;
					
					

配置标志

These configuration flags can be used to enable certain features for the material.

#define QSSG_ENABLE_UV0 1/0
#define QSSG_ENABLE_WORLD_POSITION 1/0
#define QSSG_ENABLE_TEXTAN 1/0
#define QSSG_ENABLE_BINORMAL 1/0
					

Flag	Desctiption
QSSG_ENABLE_UV0	Enables texture coordinate 0 variable.
QSSG_ENABLE_WORLD_POSITION	Enables world position variable.
QSSG_ENABLE_TEXTAN	Enables tangent variable.
QSSG_ENABLE_BINORMAL	Enables binormal variable.

配置特征

These flags are conditionally enabled by the material system when the material is being compiled. The custom shader can use them to enable different code paths for compilation.

#define QSSG_ENABLE_CG_LIGHTING
#define QSSG_ENABLE_LIGHT_PROBE
#define QSSG_ENABLE_SSAO
#define QSSG_ENABLE_SSDO
#define QSSG_ENABLE_SSM
#define QSSG_ENABLE_RNM
					

注意： Normal-mapped radiosity is not currently supported.

Flag	Desctiption
QSSG_ENABLE_CG_LIGHTING	Enabled when lighting is enabled.
QSSG_ENABLE_LIGHT_PROBE	Enabled when light probe is enabled.
QSSG_ENABLE_SSAO	Enabled when screen space ambient occlusion is enabled.
QSSG_ENABLE_SSDO	Enabled when screen space direct occlusion is enabled.
QSSG_ENABLE_SSM	Enabled when shadow mapping is enabled.
QSSG_ENABLE_RNM	Enabled when normal-mapped radiosity is enabled.

#define mono_alpha 0
#define mono_average 1
#define mono_luminance 2
#define mono_maximum 3
struct texture_return
{
    vec3 tint;
    float mono;
};
struct color_layer
{
    vec3 layer_color;
    float weight;
    int mode;
};
#include "blendColorLayers.glsllib"
texture_return blendColorLayers( in color_layer colorLayer[1], in vec3 base, in int monoSource );
				

#include "luminance.glsllib"
#include "monoChannel.glsllib"
#define wrap_clamp 0
#define wrap_repeat 1
#define wrap_mirrored_repeat 2
#include "rotationTranslationScale.glsllib"
#include "transformCoordinate.glsllib"
					
				

#define scatter_reflect 0
#define scatter_transmit 1
#define scatter_reflect_transmit 2
#include "calculateRoughness.glsllib"
#include "microfacetBSDF.glsllib"
vec4 microfacetBSDF( in mat3 tanFrame, in vec3 L, in vec3 V, in vec3 lightSpecular, in float ior,
                     in float roughnessU, in float roughnessV, in int mode )
				

vec4 microfacetSampledBSDF( in mat3 tanFrame, in vec3 viewDir, in float roughnessU,
                            in float roughnessV, in int mode )
				

#define scatter_reflect 0
#define scatter_transmit 1
#define scatter_reflect_transmit 2
#include "physGlossyBSDF.glsllib"
vec4 kggxGlossyBSDF( in mat3 tanFrame, in vec3 L, in vec3 V, in vec3 lightSpecular, in float ior,
                     in float roughnessU, in float roughnessV, in int mode )
				

vec4 wardGlossyBSDF( in mat3 tanFrame, in vec3 L, in vec3 V, in vec3 lightSpecular, in float ior,
                     in float roughnessU, in float roughnessV, in int mode )
				

#define scatter_reflect 0
#define scatter_transmit 1
#define scatter_reflect_transmit 2
#include "calculateRoughness.glsllib"
#include "simpleGlossyBSDF.glsllib"
vec4 simpleGlossyBSDF( in mat3 tanFrame, in vec3 L, vec3 V, in vec3 lightSpecular, in float ior,
                       in float roughnessU, in float roughnessV, in int mode )
				

vec4 simpleGlossyBSDFEnvironment( in mat3 tanFrame, in vec3 viewDir, in float roughnessU,
                                  in float roughnessV, in int mode )
				

#include "sampleProbe.glsllib"
vec4 sampleGlossy( mat3 tanFrame, vec3 viewDir, float roughness )
				

vec4 sampleDiffuse( mat3 tanFrame )
				

#include "sampleArea.glsllib"
vec4 sampleAreaGlossy( in mat3 tanFrame, in vec3 pos, in int lightIdx, in vec3 viewDir,
                       in float roughnessU, in float roughnessV )
				

vec4 sampleAreaDiffuse( in mat3 tanFrame, in vec3 pos, in int lightIdx )
				

out vec4 fragColor;
void main()
{
    fragColor = ...
}
					
				

#define QSSG_ENABLE_UV0 1
#define QSSG_ENABLE_WORLD_POSITION 1
#define QSSG_ENABLE_TEXTAN 0
#define QSSG_ENABLE_BINORMAL 0
#include "vertexFragmentBase.glsllib"
#include "SSAOCustomMaterial.glsllib"
#include "sampleLight.glsllib"
#include "sampleProbe.glsllib"
#include "sampleArea.glsllib"
// Set shader output.
out vec4 fragColor;
void main()
{
    vec4 c = texture(basecolor, varTexCoord0.xy);
    c.rgb *= vec3(red_weight, green_weight, blue_weight);
    fragColor = c;
}
					
				

in vec3 attr_pos;
uniform mat4 modelViewProjection;
out vec3 pos;
void main() {
    pos = attr_pos;
    pos.x += sin(time * 4.0 + pos.y) * amplitude;
    gl_Position = modelViewProjection * vec4(pos, 1.0);
}
					
				

in vec3 attr_pos;
in vec3 attr_norm;
in vec2 attr_uv0;
in vec3 attr_textan;
in vec3 attr_binormal;
				

uniform mat4 modelMatrix;
uniform mat4 modelViewProjection;
uniform mat4 viewMatrix;
uniform mat3 normalMatrix;
uniform mat4 viewProjectionMatrix;
uniform mat4 viewportMatrix;
uniform vec3 cameraPosition;
uniform vec2 cameraProperties;
uniform sampler2D depthTexture;
uniform sampler2D aoTexture;
uniform sampler2D lightProbe;
uniform vec4 lightProbeProperties;
uniform vec4 lightProbeOptions;
uniform vec4 lightProbeRotation;
uniform vec4 lightProbeOffset;
uniform sampler2D lightProbe2;
uniform vec4 lightProbe2Properties;
uniform int lightCount;
uniform int areaLightCount;
uniform int shadowMapCount;
uniform int shadowCubeCount;
uniform float objectOpacity;
uniform sampler2D shadowMaps[8];
uniform samplerCube shadowCubes[8];