1st installment of gizmos

xs/src/slic3r/GUI/GLTexture.cpp

@@ -0,0 +1,138 @@
+#include "GLTexture.hpp"
+
+#include <GL/glew.h>
+
+#include <wx/image.h>
+
+#include <vector>
+
+namespace Slic3r {
+namespace GUI {
+
+GLTexture::GLTexture()
+    : m_id(0)
+    , m_width(0)
+    , m_height(0)
+    , m_source("")
+{
+}
+
+GLTexture::~GLTexture()
+{
+    reset();
+}
+
+bool GLTexture::load_from_file(const std::string& filename)
+{
+    reset();
+
+    // Load a PNG with an alpha channel.
+    wxImage image;
+    if (!image.LoadFile(filename, wxBITMAP_TYPE_PNG))
+    {
+        reset();
+        return false;
+    }
+
+    m_width = image.GetWidth();
+    m_height = image.GetHeight();
+    int n_pixels = m_width * m_height;
+
+    if (n_pixels <= 0)
+    {
+        reset();
+        return false;
+    }
+
+    // Get RGB & alpha raw data from wxImage, pack them into an array.
+    unsigned char* img_rgb = image.GetData();
+    if (img_rgb == nullptr)
+    {
+        reset();
+        return false;
+    }
+
+    unsigned char* img_alpha = image.GetAlpha();
+
+    std::vector<unsigned char> data(n_pixels * 4, 0);
+    for (int i = 0; i < n_pixels; ++i)
+    {
+        int data_id = i * 4;
+        int img_id = i * 3;
+        data[data_id + 0] = img_rgb[img_id + 0];
+        data[data_id + 1] = img_rgb[img_id + 1];
+        data[data_id + 2] = img_rgb[img_id + 2];
+        data[data_id + 3] = (img_alpha != nullptr) ? img_alpha[i] : 255;
+    }
+
+    // sends data to gpu
+    ::glGenTextures(1, &m_id);
+    ::glBindTexture(GL_TEXTURE_2D, m_id);
+    ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1);
+    ::glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, (GLsizei)m_width, (GLsizei)m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, (const void*)data.data());
+    ::glBindTexture(GL_TEXTURE_2D, 0);
+
+    m_source = filename;
+    return true;
+}
+
+void GLTexture::reset()
+{
+    if (m_id != 0)
+        ::glDeleteTextures(1, &m_id);
+
+    m_id = 0;
+    m_width = 0;
+    m_height = 0;
+    m_source = "";
+}
+
+unsigned int GLTexture::get_id() const
+{
+    return m_id;
+}
+
+int GLTexture::get_width() const
+{
+    return m_width;
+}
+
+int GLTexture::get_height() const
+{
+    return m_height;
+}
+
+const std::string& GLTexture::get_source() const
+{
+    return m_source;
+}
+
+void GLTexture::render_texture(unsigned int tex_id, float left, float right, float bottom, float top)
+{
+    ::glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
+
+    ::glDisable(GL_LIGHTING);
+    ::glEnable(GL_BLEND);
+    ::glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    ::glEnable(GL_TEXTURE_2D);
+
+    ::glBindTexture(GL_TEXTURE_2D, (GLuint)tex_id);
+
+    ::glBegin(GL_QUADS);
+    ::glTexCoord2d(0.0f, 1.0f); ::glVertex3f(left, bottom, 0.0f);
+    ::glTexCoord2d(1.0f, 1.0f); ::glVertex3f(right, bottom, 0.0f);
+    ::glTexCoord2d(1.0f, 0.0f); ::glVertex3f(right, top, 0.0f);
+    ::glTexCoord2d(0.0f, 0.0f); ::glVertex3f(left, top, 0.0f);
+    ::glEnd();
+
+    ::glBindTexture(GL_TEXTURE_2D, 0);
+
+    ::glDisable(GL_TEXTURE_2D);
+    ::glDisable(GL_BLEND);
+    ::glEnable(GL_LIGHTING);
+}
+
+} // namespace GUI
+} // namespace Slic3r