Almost exact duplicate question: OpenGL font rendering using Freetype2.
I am trying to render text in my OpenGL program using FreeType2 (2.5.3), based on this tutorial: http://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_Text_Rendering_02, using the same structs as Bentebent did in his question (above).
I am having the same problem he was having with rectangles showing up instead of legible characters (even using the correct GL_TEXTURE0 parameter for glActiveTexture())
For example, rendering green strings "Hello" and "World" below it gives me this:
As with Bentebent, using gDebugger I can see that my textures are generated fine. I have scoured google/stackoverflow, tried different parameters for glTexImage2D, different formulas for color in my fragment shader, etc, but no luck. Been stuck for a while now. Any help is appreciated.
Structs to create texture atlas:
//DrawTestOpenGLWnd.h struct FontCharacter { float advanceX; float advanceY; float bitmapWidth; float bitmapHeight; float bitmapLeft; float bitmapTop; float uvOffsetX; float uvOffsetY; }; struct FontTextureAtlas { GLuint texture; GLint textureUniform; int width; int height; FontCharacter characters[128]; FontTextureAtlas(FT_Face face, int h, GLint tUniform) { FT_Set_Pixel_Sizes(face, 0, h); FT_GlyphSlot glyphSlot = face->glyph; int roww = 0; int rowh = 0; width = 0; height = 0; memset(characters, 0, sizeof(FontCharacter)); for (int i = 32; i bitmap.width + 1 >= MAX_WIDTH) { width = std::max(width, roww); height += rowh; roww = 0; rowh = 0; } roww += glyphSlot->bitmap.width + 1; rowh = std::max(rowh, glyphSlot->bitmap.rows); } width = std::max(width, roww); height += rowh; glGenTextures(1, &texture); if (glGetError() != GL_NO_ERROR){ TRACE("glGenTextures failed\n"); } glActiveTexture(GL_TEXTURE0); if (glGetError() != GL_NO_ERROR){ TRACE("glActiveTexture failed\n"); } glBindTexture(GL_TEXTURE_2D, texture); if (glGetError() != GL_NO_ERROR){ TRACE("glBindTexture failed\n"); } glUniform1i(tUniform, 0); textureUniform = tUniform; glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, 0); if (glGetError() != GL_NO_ERROR){ TRACE("glTexImage2D failed\n"); } glPixelStorei(GL_UNPACK_ALIGNMENT, 1); if (glGetError() != GL_NO_ERROR){ TRACE("glPixelStorei failed\n"); } glPixelStorei(GL_PACK_ALIGNMENT, 1); if (glGetError() != GL_NO_ERROR){ TRACE("glPixelStorei failed\n"); } glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); if (glGetError() != GL_NO_ERROR){ TRACE("glTexParameteri failed\n"); } glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); if (glGetError() != GL_NO_ERROR){ TRACE("glTexParameteri failed\n"); } glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); if (glGetError() != GL_NO_ERROR){ TRACE("glTexParameteri failed\n"); } glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); if (glGetError() != GL_NO_ERROR){ TRACE("glTexParameteri failed\n"); } int ox = 0; int oy = 0; rowh = 0; for (int i = 32; i bitmap.width + 1 >= MAX_WIDTH) { oy += rowh; rowh = 0; ox = 0; } glTexSubImage2D(GL_TEXTURE_2D, 0, ox, oy, glyphSlot->bitmap.width, glyphSlot->bitmap.rows, GL_RED, GL_UNSIGNED_BYTE, glyphSlot->bitmap.buffer); if (glGetError() != GL_NO_ERROR) { TRACE("BORKED AGAIN\n"); } characters[i].advanceX = glyphSlot->advance.x >> 6; characters[i].advanceY = glyphSlot->advance.y >> 6; characters[i].bitmapWidth = glyphSlot->bitmap.width; characters[i].bitmapHeight = glyphSlot->bitmap.rows; characters[i].bitmapLeft = glyphSlot->bitmap_left; characters[i].bitmapTop = glyphSlot->bitmap_top; characters[i].uvOffsetX = ox / (float)width; characters[i].uvOffsetY = oy / (float)height; rowh = std::max(rowh, glyphSlot->bitmap.rows); ox += glyphSlot->bitmap.width + 1; } TRACE("Generated a %d x %d (%d kb) texture atlas.\n", width, height, width * height / 1024); } ~FontTextureAtlas() { glDeleteTextures(1, &texture); } }; InitFreeType function:
void DrawTestOpenGLWnd::InitFreeType(char * strFontFilePath) { m_error = FT_Init_FreeType(&m_library); if (m_error) { TRACE("An error occurred during library initialization"); } m_error = FT_New_Face(m_library, strFontFilePath, 0, &m_face); if (m_error == FT_Err_Unknown_File_Format) { TRACE("Font file could be opened and read, but it appears that its font format is unsupported"); } else if (m_error) { TRACE("Font file could not be opened or read. Or it's broken."); } m_program_text = LoadShaders("TextVertexShader.vertexshader", "TextFragmentShader.fragmentshader"); glUseProgram(m_program_text); m_uniform_texture = glGetUniformLocation(m_program_text, "texture"); m_uniform_textColor = glGetUniformLocation(m_program_text, "textColor"); glGenVertexArrays(1, &vao_text); glBindVertexArray(vao_text); glGenBuffers(1, &vbo_text); //glBindBuffer(GL_ARRAY_BUFFER, vbo_text); a48 = new FontTextureAtlas(m_face, 48, m_uniform_texture); a24 = new FontTextureAtlas(m_face, 24, m_uniform_texture); a12 = new FontTextureAtlas(m_face, 12, m_uniform_texture); } RenderText function:
void DrawTestOpenGLWnd::RenderText(char * text, FontTextureAtlas * atlas, float x, float y, float sx, float sy) { glUseProgram(m_program_text); const unsigned char* p; std::vector<:vec4> coords; int c = 0; for (p = (const unsigned char*)text; *p; p++) { float x2 = x + atlas->characters[*p].bitmapLeft * sx; float y2 = -y - atlas->characters[*p].bitmapTop * sy; float w = atlas->characters[*p].bitmapWidth * sx; float h = atlas->characters[*p].bitmapHeight * sy; x += atlas->characters[*p].advanceX * sx; y += atlas->characters[*p].advanceY * sy; if (!w || !h) continue; coords.push_back( glm::vec4( x2, -y2, atlas->characters[*p].uvOffsetX, atlas->characters[*p].uvOffsetY) ); coords.push_back( glm::vec4( x2 + w, -y2, atlas->characters[*p].uvOffsetX + atlas->characters[*p].bitmapWidth / atlas->width, atlas->characters[*p].uvOffsetY) ); coords.push_back( glm::vec4( x2, -y2 - h, atlas->characters[*p].uvOffsetX, atlas->characters[*p].uvOffsetY + atlas->characters[*p].bitmapHeight / atlas->height) ); coords.push_back( glm::vec4( x2 + w, -y2, atlas->characters[*p].uvOffsetX + atlas->characters[*p].bitmapWidth / atlas->width, atlas->characters[*p].uvOffsetY) ); coords.push_back( glm::vec4( x2, -y2 - h, atlas->characters[*p].uvOffsetX, atlas->characters[*p].uvOffsetY + atlas->characters[*p].bitmapHeight / atlas->height) ); coords.push_back( glm::vec4( x2 + w, -y2 - h, atlas->characters[*p].uvOffsetX + atlas->characters[*p].bitmapWidth / atlas->width, atlas->characters[*p].uvOffsetY + atlas->characters[*p].bitmapHeight / atlas->height) ); } glBindVertexArray(vao_text); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glActiveTexture(GL_TEXTURE0); glUniform1i(atlas->textureUniform, 0); glBindTexture(GL_TEXTURE_2D, atlas->texture); GLfloat textColor[4] = {0.0, 1.0, 0.0, 0.}; //green glUniform4fv(m_uniform_textColor, 1, textColor); glBindBuffer(GL_ARRAY_BUFFER, vbo_text); glBufferData(GL_ARRAY_BUFFER, coords.size() * sizeof(glm::vec4), coords.data(), GL_DYNAMIC_DRAW); //Position glEnableVertexAttribArray(0); glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(glm::vec4), (void*)0); glDrawArrays(GL_TRIANGLES, 0, coords.size()); glDisableVertexAttribArray(0); glBindVertexArray(0); glUseProgram(0); } TextVertexShader.vertexshader:
#version 330 core layout(location = 0) in vec4 pos_uv; out vec2 uv; void main(void) { gl_Position = vec4(pos_uv.xy, 0, 1); uv = pos_uv.zw; } TextFragmentShader.fragmentshader:
#version 330 core in vec2 uv; uniform sampler2D texture; uniform vec4 textColor; out vec4 color; void main(void) { color = vec4(textColor.rgb, texture2D(texture, uv).a); }