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https://github.com/vallentin/gltext
Cross-platform single header text rendering library for OpenGL
https://github.com/vallentin/gltext
c computer-graphics cpp drawing graphics opengl rendering text
Last synced: 10 days ago
JSON representation
Cross-platform single header text rendering library for OpenGL
- Host: GitHub
- URL: https://github.com/vallentin/gltext
- Owner: vallentin
- License: zlib
- Created: 2016-05-12T18:33:40.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2023-05-30T07:51:13.000Z (over 1 year ago)
- Last Synced: 2024-10-14T14:11:15.418Z (23 days ago)
- Topics: c, computer-graphics, cpp, drawing, graphics, opengl, rendering, text
- Language: C
- Homepage:
- Size: 29.3 KB
- Stars: 166
- Watchers: 4
- Forks: 17
- Open Issues: 20
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
Awesome Lists containing this project
README
# glText
[![Build Status][glTextBuildStatus]][glTextCI]
![Release][glTextVersionBadge]
![Supported OpenGL 3.3][glTextOpenGLVersionsBadge]
![License][glTextLicenseBadge]
[glText][glText] is a simple cross-platform single header text rendering
library for OpenGL. [glText][glText] requires no additional files
(such as fonts or textures) for drawing text, everything comes pre-packed
in the header.
*The above screenshot is of the [simple.c](examples/simple.c) example.*
## Example
```c
// Initialize glText
gltInit();
// Creating text
GLTtext *text = gltCreateText();
gltSetText(text, "Hello World!");
// Begin text drawing (this for instance calls glUseProgram)
gltBeginDraw();
// Draw any amount of text between begin and end
gltColor(1.0f, 1.0f, 1.0f, 1.0f);
gltDrawText2D(text, x, y, scale);
// Finish drawing text
gltEndDraw();
// Deleting text
gltDeleteText(text);
// Destroy glText
gltTerminate();
```
## Implementation
In one C or C++ file, define `GLT_IMPLEMENTATION` prior to inclusion to create the implementation.
```c
#define GLT_IMPLEMENTATION
#include "gltext.h"
```
## Optimization
Each time `gltDraw*()` functions are called, `glGetIntegerv(GL_VIEWPORT, ...)`
is called. To avoid this and optimize that call away, define `GLT_MANUAL_VIEWPORT`
before including `gltext.h`.
```c
#define GLT_MANUAL_VIEWPORT
#include "gltext.h"
```
Then when the viewport is resized manually call:
```c
gltViewport(width, height)
```
## Manual Model, View, Projection Matrix
The example uses [LinearAlgebra](https://github.com/vallentin/LinearAlgebra).
```c
GLfloat fontScale = 0.01f;
GLfloat x = 0.0f;
GLfloat y = 0.0f;
x -= gltGetTextWidth(text, fontScale) * 0.5f;
y -= gltGetTextHeight(text, fontScale) * 0.5f;
mat4 proj = mat4::perspective(70.0f, viewportWidth, viewportHeight, 0.1f, 10.0f);
mat4 view = ...;
mat4 model = mat4::identity;
model.translate(x, y + gltGetTextHeight(text, fontScale));
model.scale(fontScale, -fontScale);
mat4 mvp = proj * view * model;
gltDrawText(text, (GLfloat*)&mvp);
```
## Aligned Text
```c
// Where horizontal is either:
// - GLT_LEFT (default)
// - GLT_CENTER
// - GLT_RIGHT
// Where vertical is either:
// - GLT_TOP (default)
// - GLT_CENTER
// - GLT_BOTTOM
gltDrawText2DAligned(text, x, y, scale, horizontal, vertical);
```
## No Dependencies
[glText][glText] has no external dependencies besides [OpenGL][OpenGL] and the standard C libraries.
By default [glText][glText] uses `stdlib.h`, `string.h` and `stdint.h`.
If `GLT_DEBUG` is defined `assert.h` is needed. If `GLT_DEBUG_PRINT` is defined `stdio.h` is needed.
## Reporting Bugs & Requests
Feel free to use the [issue tracker][glTextIssues],
for reporting bugs, submitting patches or requesting features.
Before submitting bugs, make sure that you're using the latest version of [glText][glText].
[glText]: https://github.com/vallentin/glText
[glTextReleases]: https://github.com/vallentin/glText/releases
[glTextBuildStatus]: https://drone.io/github.com/vallentin/glText/status.png
[glTextCI]: https://drone.io/github.com/vallentin/glText/latest
[glTextVersionBadge]: https://img.shields.io/badge/release-v1.1.6-blue.svg
[glTextLicenseBadge]: https://img.shields.io/badge/license-%20free%20to%20use%2C%20share%2C%20modify%20and%20redistribute-blue.svg
[glTextOpenGLVersionsBadge]: https://img.shields.io/badge/OpenGL-3.3-blue.svg
[glTextIssues]: https://github.com/vallentin/glText/issues
[OpenGL]: https://en.wikipedia.org/wiki/OpenGL