generate skin preview

Signed-off-by: Trial97 <alexandru.tripon97@gmail.com>

launcher/minecraft/skins/SkinModel.cpp

@@ -18,10 +18,13 @@
 
 #include "SkinModel.h"
 #include <QFileInfo>
+#include <QOffscreenSurface>
+#include <QOpenGLFramebufferObjectFormat>
 #include <QPainter>
 
 #include "FileSystem.h"
 #include "Json.h"
+#include "ui/dialogs/skins/draw/Scene.h"
 
 QImage improveSkin(const QImage& skin)
 {
@@ -45,7 +48,106 @@ QImage getSkin(const QString path)
     return improveSkin(QImage(path));
 }
 
-SkinModel::SkinModel(QString path) : m_path(path), m_texture(getSkin(path)), m_model(Model::CLASSIC) {}
+QImage generatePreviews(QImage texture, bool slim)
+{
+    QImage preview;
+
+    // Set up OpenGL context and offscreen surface
+    QOpenGLContext context;
+    context.setFormat(QSurfaceFormat::defaultFormat());
+    if (!context.create()) {
+        qWarning() << "Failed to create OpenGL context";
+        return preview;
+    }
+
+    QOffscreenSurface surface;
+    surface.setFormat(context.format());
+    surface.create();
+
+    // Make the OpenGL context current
+    context.makeCurrent(&surface);
+
+    QOpenGLFunctions* gl = context.functions();
+    QOpenGLFramebufferObjectFormat fboFormat;
+    fboFormat.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
+
+    QOpenGLShaderProgram program;
+    // Compile vertex shader
+    if (!program.addCacheableShaderFromSourceFile(QOpenGLShader::Vertex, ":/shaders/vshader.glsl")) {
+        qWarning() << "Failed to create vertex";
+        return preview;
+    }
+    // Compile fragment shader
+    if (!program.addCacheableShaderFromSourceFile(QOpenGLShader::Fragment, ":/shaders/fshader.glsl")) {
+        qWarning() << "Failed to create fragment";
+        return preview;
+    }
+    // Link shader pipeline
+    if (!program.link()) {
+        qWarning() << "Failed to create link";
+        return preview;
+    }
+    // Bind shader pipeline for use
+    if (!program.bind()) {
+        qWarning() << "Failed to create bind";
+        return preview;
+    }
+    auto scene = new opengl::Scene(texture, slim, {});
+
+    const qreal zNear = .1, zFar = 1000., fov = 45, aspect = 1;
+
+    // Reset projection
+    QMatrix4x4 m_projection;
+    m_projection.setToIdentity();
+
+    // Set perspective projection
+    m_projection.perspective(fov, aspect, zNear, zFar);
+
+    // Calculate model view transformation
+    QMatrix4x4 matrix;
+    matrix.translate(0.0, 6.0, -50.);
+
+    // Create a framebuffer object for rendering
+    QOpenGLFramebufferObject fbo(64, 64, fboFormat);
+    fbo.bind();
+
+    // Clear the framebuffer
+    gl->glViewport(0, 0, 64, 64);
+    gl->glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+    // Clear color and depth buffer
+    gl->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    // Enable depth buffer
+    gl->glEnable(GL_DEPTH_TEST);
+    gl->glDepthFunc(GL_LESS);
+
+    // Enable back face culling
+    gl->glEnable(GL_CULL_FACE);
+
+    gl->glEnable(GL_BLEND);
+    gl->glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+    // Set modelview-projection matrix
+    program.setUniformValue("mvp_matrix", m_projection * matrix);
+
+    // scene->setMode(skin->getModel() == SkinModel::SLIM);
+    // scene->setSkin(skin->getTexture());
+
+    scene->draw(&program);
+
+    // Read the framebuffer into a QImage
+    preview = fbo.toImage();
+
+    fbo.release();
+    delete scene;
+    context.doneCurrent();
+    return preview;
+}
+
+SkinModel::SkinModel(QString path) : m_path(path), m_texture(getSkin(path)), m_model(Model::CLASSIC)
+{
+    m_preview = generatePreviews(m_texture, false);
+}
 
 SkinModel::SkinModel(QDir skinDir, QJsonObject obj)
     : m_capeId(Json::ensureString(obj, "capeId")), m_model(Model::CLASSIC), m_url(Json::ensureString(obj, "url"))
@@ -57,6 +159,7 @@ SkinModel::SkinModel(QDir skinDir, QJsonObject obj)
     }
     m_path = skinDir.absoluteFilePath(name) + ".png";
     m_texture = QImage(getSkin(m_path));
+    m_preview = generatePreviews(m_texture, m_model == Model::SLIM);
 }
 
 QString SkinModel::name() const
@@ -99,4 +202,5 @@ bool SkinModel::isValid() const
 void SkinModel::refresh()
 {
     m_texture = getSkin(m_path);
+    m_preview = generatePreviews(m_texture, m_model == Model::SLIM);
 }