Qt opengl assimp使用骨骼动画代码

下面是使用Qt、OpenGL和Assimp实现骨骼动画的示例代码：

首先，我们需要加载模型文件，并从中获取必要的数据。下面的代码片段演示了如何使用Assimp加载模型文件：

#include <assimp/Importer.hpp>
#include <assimp/scene.h>
#include <assimp/postprocess.h>
#include <vector>

// 从文件中加载模型
Assimp::Importer importer;
const aiScene* scene = importer.ReadFile("model_file_path", aiProcess_Triangulate | aiProcess_FlipUVs | aiProcess_CalcTangentSpace);

// 获取模型中的骨骼信息
const aiMesh* mesh = scene->mMeshes[0];
const aiBone** bones = mesh->mBones;
int num_bones = mesh->mNumBones;

// 获取骨骼的全局变换矩阵
std::vector<glm::mat4> bone_transforms(num_bones);
for (int i = 0; i < num_bones; ++i) {
    const aiBone* bone = bones[i];
    bone_transforms[i] = toGLM(bone->mOffsetMatrix);
}

接下来，我们需要计算每个骨骼的本地变换矩阵。这可以通过递归遍历骨骼树来完成。下面是计算本地变换矩阵的示例代码：

// 计算每个骨骼的本地变换矩阵
std::vector<glm::mat4> bone_local_transforms(num_bones);
const aiNode* root_node = scene->mRootNode;
const glm::mat4 identity_matrix(1.0f);
processNode(root_node, identity_matrix, bone_local_transforms, bones, num_bones);

void processNode(const aiNode* node, const glm::mat4& parent_transform, std::vector<glm::mat4>& bone_local_transforms, const aiBone** bones, int num_bones) {
    glm::mat4 node_transform = toGLM(node->mTransformation);
    glm::mat4 global_transform = parent_transform * node_transform;

    // 如果该节点对应一个骨骼，则计算其本地变换矩阵
    const aiBone* bone = findBone(node->mName.C_Str(), bones, num_bones);
    if (bone) {
        glm::mat4 bone_transform = global_transform * toGLM(bone->mOffsetMatrix);
        bone_local_transforms[bone->mIndex] = bone_transform;
    }

    // 递归遍历子节点
    for (int i = 0; i < node->mNumChildren; ++i) {
        processNode(node->mChildren[i], global_transform, bone_local_transforms, bones, num_bones);
    }
}

const aiBone* findBone(const char* name, const aiBone** bones, int num_bones) {
    for (int i = 0; i < num_bones; ++i) {
        if (strcmp(name, bones[i]->mName.C_Str()) == 0) {
            return bones[i];
        }
    }
    return nullptr;
}

现在，我们可以在每个顶点上应用骨骼变换。下面是应用骨骼变换的示例代码：

// 应用骨骼变换
std::vector<glm::mat4> bone_transforms(num_bones);
for (int i = 0; i < num_bones; ++i) {
    const aiBone* bone = bones[i];
    int bone_index = bone->mIndex;
    bone_transforms[bone_index] = bone_local_transforms[bone_index] * bone_transforms[bone->mParent ? bone->mParent->mIndex : -1];
}

// 将骨骼变换矩阵传递给顶点着色器
glUniformMatrix4fv(glGetUniformLocation(shader_program, "bone_transforms"), num_bones, GL_FALSE, glm::value_ptr(bone_transforms[0]));

最后，我们需要在顶点着色器中应用骨骼变换。下面是一个简单的顶点着色器示例：

#version 330 core

layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texcoord;
layout (location = 3) in ivec4 bone_ids;
layout (location = 4) in vec4 bone_weights;

uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
uniform mat4 bone_transforms[100];

out vec3 frag_normal;
out vec2 frag_texcoord;

void main() {
    vec4 world_pos = model * vec4(position, 1.0);
    vec4 bone_pos = vec4(0.0, 0.0, 0.0, 0.0);

    for (int i = 0; i < 4; ++i) {
        int bone_id = bone_ids[i];
        float bone_weight = bone_weights[i];
        bone_pos += bone_weight * bone_transforms[bone_id] * world_pos;
    }

    gl_Position = projection * view * bone_pos;
    frag_normal = mat3(transpose(inverse(model))) * normal;
    frag_texcoord = texcoord;
}

这样，我们就可以在OpenGL中实现骨骼动画了。